Abstract
Saturday, October 6, 2018
Thyroid Nodules & Goiter Saturday Oral Translational 8:50 AM
Thyroid hyperplasia/multinodular goiter, characterized by cellular and follicular overgrowth, is a very common endocrine condition, resulting in various functional and structural consequences and certain malignant potential. Its genetic background is completely unknown. Given previous genetic and epigenetic data suggesting that RASAL1 might be a thyroid tumor suppressor gene, particularly in follicular thyroid neoplasm, we hypothesized that the RASAL1 gene could play a fundamental role in the development of thyroid hyperplasia/multinodular goiter. To explore the role of the RASAL1 gene in the development of thyroid hyperplasia/multinodular goiter, we developed a novel Rasal1 knockout mouse model using the CRISPR/Cas9 approach and the C57BL/6J zygotes, followed by observing the pathological changes in the thyroid gland of the knockout mice in comparison with the wild-type mice. We successfully created a novel Rasal1 knockout mouse model with establishment of several generations of mice carrying the heterozygous and homozygous knockout of the Rasal1 gene at exon 2, which was confirmed by genetic testing and by Western blotting of the Rasal1 protein. All the mice with Rasal1 knockout, whether heterozygous or homozygous, developed grossly visible multinodular goiter with microscopic confirmation of follicular cell hyperplasia, with occasional case showing thyroid cancer. In contrast, only occasional case of aged wild-type mice developed thyroid hyperplasia and no wild-type mice developed thyroid malignancy. These data demonstrate that defect of Rasal1 can cause full and complete development of thyroid hyperplasia/multinodular goiter in mice. Given the striking similarity of thyroid hyperplasia/multinodular goiter in these Rasal1 knockout mice with that in humans, it is plausible to suggest that RASAL1 is a master gene involved in the development and pathogenesis of human thyroid hyperplasia/ multinodular goiter. This project also provides a new genetic knockout mouse model for future study of thyroid neoplasm.
Thyroid Cancer Saturday Oral Translational 9:05 AM
Anaplastic thyroid cancer (ATC) is an aggressive malignancy with limited treatment options. Targeting epigenetic modifications via interference of the acetylated histone binding by bromodomain and extra-terminal domain (BET) proteins using inhibitors (e.g., JQ1) has shown some efficacy in thyroid cancer. In the present preclinical studies, we evaluated the efficacy of a novel BET inhibitor, PLX51107 (PLX), currently in clinical trials for other solid tumors and hematologic malignancies, singly or with a MEK inhibitor, PD0325901(PD) in the treatment of ATC. We examined the effects of PLX, PD, or their combination on the mouse xenograft tumor development of human ATC cell lines (THJ-11T and THJ-16T), each having been authenticated by DNA short tandem repeat analysis. We elucidated the underlying molecular pathways of these treatments using the collected tumor tissues. The combination treatment almost totally blocked growth in xenograft tumors induced by THJ-11T or THJ-16T cells, while either PLX or PD alone, both caused only partial reductions (40-60% by PLX; 60-70% by PD). PLX, acting through inhibition of transcription via epigenetic chromatin modifications, suppressed MYC expression, while PD effectively attenuated MEK-ERK signaling in the xenograft tumors. Importantly, the combination of PLX and PD acted synergistically to suppress MYC transcription to lower protein levels. This led to increased p27, a CDK inhibitor, thus decreasing tumor cell proliferation. PLX further suppressed the ERK signaling, leading to upregulation of BIM, a pro-apoptotic regulator, to promote tumor cell apoptosis. Together by decreasing proliferation and increasing apoptosis, the tumor growth was almost totally blocked. Combined treatment of BET and MEK-ERK inhibitors was more effective to treat ATC than single targeted treatment. Synergistic suppression of MYC transcription via collaborative actions on chromatin modifications suggested that targeting epigenetic modifications could provide novel treatment opportunities for ATC.
Thyroid Cancer Saturday Oral Translational 9:20 AM
Gene fusions are a common mechanism of thyroid cancer and play an important role in molecular diagnostics in thyroid fine-needle aspiration (FNA) samples. In addition to common RET/PTC fusions, several other fusion types were more recently described, some with potential use as a therapeutic target (eg. ALK, NTRK3). The risk of malignancy and impact on patient management for some of these fusions is not well defined. The goal of this study was to evaluate the prevalence and types of fusions detected by ThyroSeq v3 Genomic Classifier (GC) in routine FNA samples and their association with the risk of malignancy. ThyroSeq v3 GC is a DNA and RNA based next-generation sequencing assay that analyzes 112 thyroid-related genes for >12,000 genomic variants, >150 fusion types, copy number changes, and gene expression alterations. The ThyroSeq Molecular Database (ThyroSeqMD) was searched for gene fusions detected in thyroid nodules tested from 11/2017-05/2018. Available surgical follow-up was collected. Out of 6,734 nodules tested, 314 (4.7%) were positive for fusions. The most common type was THADA/IGF2BP3 detected in 121 (39%) nodules, followed by RET/PTC in 52 (17%), NTRK3 in 47 (15%), and PPARG in 47 (15%). Other fusions were found at lower prevalence, including BRAF in 14 (4%), ALK in 9 (3%), THADA/TRA2A in 8 (3%), and NTRK1 in 8 (3%) of nodules. Eight nodules had rare fusions (e.g. FGFR2/VCL, UACA/LTK, TFG/MET). The follow-up was collected on 47 (15%) positive cases and is ongoing. The risk of malignancy/NIFTP across all fusion types was 92%. RET/PTC, NTRK3, NTRK1, and ALK fusions were all PTC. THADA/IGF2BP3 was found in NIFTP (50%), PTC (40%) and FTC (10%). PPARG fusions were associated with FTC (25%), HCC (25%), PTC (25%) and benign (25%) nodules. One BRAF fusion (SND1/BRAF) was found in FA, and the rest were PTC. Approximately 5% of tested thyroid nodules were positive for gene fusions. THADA/IGF2BP3 was the most common type, followed by RET/PTC, NTRK3, and PPARG fusions. The overall probability of cancer or NIFTP in these nodules was 92% and it varied in specific fusion types. In addition to diagnostic utility, some of the detected fusions (ALK, NTRK1/3) may be used as therapeutic targets in advanced cancers.
Thyroid Hormone Action Saturday Oral Translational 9:35 AM
Glycogen storage disease type Ia (GSD Ia), is an inherited deficiency of glucose-6-phosphatase (G6Pase), the enzyme that catalyzes the last step of gluconeogenesis. This deficiency leads to over-accumulation of hepatic glycogen and triglycerides that eventuates in non-alcoholic fatty liver disease (NAFLD). We previously showed that there is decreased intrahepatic T3 concentration in a rodent model of NAFLD. We also showed that T3 stimulated autophagy of fat droplets (lipophagy) to increase β-oxidation of fatty acids in the liver. Moreover, we found that low dose levothyroxine supplementation reduced hepatosteatosis in a pilot study of euthyroid diabetic Asian male patients with NAFLD. Our earlier studies in G6pc -/-mice with GSD Ia and dogs with GSD Ia demonstrated deficient hepatic autophagy that was rescued by treatment with rapamycin, and led to reductions in hepatic glycogen and triglyceride concentrations. Accordingly, we investigated the efficacy of liver-selective thyromimetic, VK2809, to reduce hepatic triglyceride concentrations in G6pc -/-knockout mice. Wild type and knockout mice were treated with intraperitoneal injections of vehicle or compound (10 ug/g BW) for 4 days shortly after birth, and then sacrificed and livers harvested/assayed at 9 days of age. VK2809 reduced hepatic triglyceride concentration by 75% although it did not affect hepatic glycogen accumulation. VK2809 restored hepatic autophagy by increasing LC3II and decreasing p62 protein expression. VK2809 also increased the expression of PGC1a, a known stimulator of mitochondrial biogenesis as well as COXIV and VDAC mitochondrial proteins. It also increased expression of CPT1α the rate-determining fatty acid carrier protein essential for mitochondrial β-oxidation of fatty acids. Histological examination showed decreased hepatic steatosis, inflammation, and fibrosis in mice treated with VK2809. In summary, our findings showed that a liver-selective TRβ agonist decreased the accumulation of triglyceride in the livers of G6pc -/-mice, and suggest that this treatment strategy may have similar beneficial effects in other conditions associated with NAFLD.
Thyroid Cancer Saturday Oral Clinical 8:50 AM
The RET kinase was identified as a key oncogenic driver of medullary thyroid cancer (MTC) and papillary thyroid cancer (PTC) over 20 years ago, yet available therapies such as multikinase inhibitors (MKI) were not designed to target RET. We report updated results in advanced, RET-altered thyroid cancer with BLU-667 novel inhibitor designed to potently and selectively target RET. Adult patients (pts) with advanced, RET-altered solid tumors received BLU-667 orally following dose escalation/expansion design. We assessed adverse events (AEs), pharmacokinetics, and best response according to RECIST 1.1. As of 20JUL18, 52 pts including 29 MTC pts (22 M918T; 7 other RET including 3 hereditary pts [1 V804M; 2 C634R]) and 2 PTC (both CCDC6-RET) pts were treated in dose escalation with BLU-667 at doses of 30-600 mg daily (QD). 50% (26/52) were MKI pre-treated (median 1; range 1-6). BLU-667 400 mg was the maximum tolerated dose and chosen dose for expansion, which is now enrolling.
Of 28 evaluable MTC pts, 1 had CR and 12 had PR for an overall response rate (ORR) of 46% (95% CI 28-66%; 11 confirmed; 2 pending confirmation) across all dose levels. Median duration of response was not reached (>1 to 9.5 months) and all responses are ongoing. 22 (79%) remain on treatment (4–15 months). ORR at 300/400 mg QD was 62% (8/13; 95% CI 32-86%) including response in 4/6 MKI pre-treated. ORR was 70% for M918T pts (10 evaluable). Of 2 PTC pts, 1 had confirmed PR and 1 with non-measurable target lesions had SD. Both are ongoing at 4.5 and 6.3 months.
Across 30-400 mg QD (N = 48) most AEs were reversible grade (Gr) 1 and there were no Gr 4/5 BLU-667-related AEs. Treatment related AEs >10% were WBC decrease (27%), AST increase (21%) and ALT increase (19%). Treatment related Gr 3 AE (>1 pt) were neutropenia/neutrophil decrease (8%), anemia (4%) and hypertension (4%). BLU-667 is well-tolerated and demonstrates significant clinical activity in advanced, RET-altered MTC and PTC regardless of RET-alteration or prior MKI therapy. These data confirm RET as an essential driver of advanced thyroid cancer and suggest improved tolerability of selective RET inhibition with BLU-667 over MKI. Further clinical development in MTC and PTC is warranted.
Thyroid Cancer Saturday Oral Clinical 9:05 AM
RET kinase alterations (fusions, mutations) are actionable cancer drivers in papillary (and other) thyroid cancer (PTC) and medullary thyroid cancer (MTC). However, the clinical activity of multikinase inhibitors (MKIs) in these patients (pts) is moderate. LOXO-292 is a highly selective RET inhibitor, with preclinical activity against RET fusions and mutations. LIBRETTO-001 (NCT03157128) is a global phase 1/2 study for pts w/ advanced solid tumors including RET fusion+ thyroid and RET mutant-MTC. Pts are dosed orally in 28-day cycles in a 3 + 3 design. The primary endpoint is MTD/recommended dose determination. Secondary endpoints include safety, ORR (RECIST 1.1) and DoR. Initial data were presented at ASCO 2018. As of 2-Apr-18, 9 RETfusion+ thyroid (8 PTC, 1 poorly-differentiated thyroid cancer) pts w/ 5 unique fusion partners and 29 RET mutant-MTC pts w/ extracellular and kinase domain mutations were treated (20 mg QD-240 mg BID). MTC pts were heavily pretreated (9/29 31% w/ 1 prior MKI, 14/29 48% w/ >1 prior MKI). The MTD was not reached. AEs (≥10% of pts) were fatigue (20%), diarrhea (16%), constipation (15%), dry mouth (12%), nausea (12%), and dyspnea (11%); most were grade (gr) 1-2. For evaluable pts, the ORR was 100% for RET fusion+ thyroid (7/7, 2 pending confirmation) and 45% for MTC (10/22, 4 pending confirmation). 2 pts w/a hereditary RET V804M gatekeeper mutation had confirmed responses (1 CR). 82% (18/22) MTC pts had tumor reductions (range −6 to −58%), and 86% (19/22) had sustained ≥50% decrease in calcitonin (range −69 to −99.7%). Most pts remain on treatment (9/9 RET fusion+ thyroid and 27/29 MTC pts), including all responders. The median DoR was not reached (longest response: >5+ months, ongoing). Rapid and sustained (≥ 50%) decreases of RET variants in cfDNA were observed in 4 of 4 (100%) assessable RET fusion+ thyroid and 11 of 13 (85%) assessable MTC pts. LOXO-292 is well-tolerated and has marked antitumor activity in RET-altered thyroid cancer pts, including those w/ resistance to prior MKIs. Phase 2 cohorts are enrolling globally (160 mg BID). Updated clinical activity, including additional enrolled pts as of July 19, 2018, will be presented.
Thyroid Cancer Saturday Oral Clinical 9:20 AM
Differentiated thyroid cancer is the most common malignancy resulting from childhood irradiation. Whether radiation-induced thyroid cancer affects survival rates has not been clearly elucidated. The objective of the current study was to determine if the development of thyroid cancer is associated with a decreased survival in radiation-exposed individuals. We have conducted a case-control survival analysis within a cohort of 4296 individuals who were irradiated for enlarged tonsils during their childhood (between 1939 and 1962) and were prospectively followed since 1974. Cases, those who developed thyroid cancer, and controls, who had not developed thyroid cancer by the time the control did, were matched and stratified for analysis according to their gender, year of birth, age at radiation treatment and radiation dose. For each cancer case, two controls were randomly selected. We then evaluated survival time, calculated starting at the date of thyroid cancer diagnosis and ending either when a death occurred or at the end of the observation period (December 31st, 2016). Vital status and causes of death were determined using the National Death Index (1979–2016), the Social Security Death Index (1974–1979), and study files. Cause of death was categorized as cardiovascular, malignancy, or other. A total of 1008 subjects were included in the analysis, including 353 thyroid cancer cases. At the end of observation, a total of 168 out of 694 (24.2%) of individuals in the control group had died compared with 94 of 353 (26.6%) of the subjects with thyroid cancer. Cox proportional hazard analysis showed no difference in survival between the thyroid cancer cases and controls (HR = 1.012 [0.77-1.33]). Survival was not different even after eliminating microcarcinomas, defined as tumor size <10 mm (HR = 1.39 [0.96-2.03]). Distribution of the causes of death taking into account age and the time of observation, differed between cases and controls (p < 0.05). In radiation-exposed individuals, development of thyroid cancer did not affect overall survival although it did affect the distribution of the causes of death.
Thyroid Cancer Saturday Oral Clinical 9:35 AM
RAI (131I) efficacy against DTC is reduced by RAF/MEK/ERK pathway activation compromising RAI uptake via downregulation of thyroid-specific gene expression, including the Na(+)/I(-) symporter. The phase III ASTRA study (NCT01843062) evaluated if adding a short course of the oral, potent and selective MEK1/2 inhibitor selumetinib (SEL; AZD6244, ARRY-142886) to single-dose adjuvant RAI improves CRR of pts with DTC. As of 18 May 2018, 233 pts ≥18 yrs with non-metastatic DTC at high risk of primary treatment failure after total thyroidectomy were randomized 2:1 to SEL 75 mg BID (n = 155) or placebo (PBO; n = 78) initiated ∼4 weeks prior to and continued through 5 days after 100 mCi (3.7 GBq) RAI. Primary objective was 18 month (mo) CRR (biochemical and structural) without further therapy after initial RAI. Biochemical remission was assessed by stimulated serum thyroglobulin and interfering thyroglobulin antibody levels; structural remission assessments included neck ultrasound and MRI, diagnostic 131I whole body scan, and chest CT. Secondary objectives included 18 mo CRR according to centrally confirmed archival tumor BRAF/NRAS mutation status, safety and tolerability.157/233 enrolled pts completed all study procedures and were eligible for 18 mo CRR assessments. CRR was 40.0% (n = 62) with SEL and 38.5% (n = 30) with PBO (OR 1.07; 95% CI 0.61, 1.87; 2-sided p = 0.82). In 142 (61%) pts with a BRAF/NRAS mutation, CRR was 37.4% (n = 34) with SEL and 41.2% (n = 21) with PBO (OR 0.85; 95% CI 0.42, 1.73; 2-sided p = 0.65). In patients with no detected BRAF/NRAS mutation (n = 61), CRR was 44.4% (n = 20) with SEL and 31.3% (n = 5) with PBO (OR 1.76; 95% CI 0.54, 6.35; 2-sided p = 0.35). AEs were reported by 98% of pts with SEL and 75% of pts with PBO; ≥G3 AEs were more frequent with SEL (18 vs 1%). 18 pts receiving SEL discontinued due to AEs. Adding SEL to postoperative RAI did not improve CRR in this high risk population. The SEL safety profile was manageable and consistent with previous data. The 38.5% CRR with standard therapy alone is the first prospective evaluation of outcomes for this population, validating previous retrospective studies. Assessing efficacy of other MAPK inhibitors may be warranted in pts with BRAF/NRAS mutations.
Thursday, October 4, 2018
Autoimmunity Thursday Poster Basic
Iso-myosmine is a synthetic derivative of myosmine, a member of the tobacco alkaloids. These compounds are endowed with immunoregulatory properties and support the epidemiological observations that smoking reduces the odds of developing thyroid antibodies and hypothyroidism. To assess the effect and mechanism(s) of action of iso-myosmine, we chose the NOD.H-2h4 mouse model where thyroiditis develops spontaneously and is accelerated by iodine administration. We began in vitro using T cells isolated from NOD.H-2h4 spleens and found that iso-myosmine suppressed in a dose-dependent fashion the ability of CD4 T cells to produce TNF-α. We then treated 58 NOD.H-2h4 mice (21 F and 37 M) for 12 weeks with either regular water (No. = 16) or water supplemented with one of following: sodium iodide (500 mg/L; No. = 16), sodium iodide (500 mg/L) plus iso-myosmine (185 mg/L; No. = 16), or iso-myosmine (185 mg/L; No. = 10). Mice were bled at baseline (8 weeks old) and then every two weeks until sacrifice. Iso-myosmine significantly decreased the incidence (p < 0.001) and severity (p < 0.001) of thyroiditis, as assessed by histopathology. Similarly, the number of CD3 T cells and CD19 B cells infiltrating the thyroid gland (which increased as expected in the iodine group), was markedly dampened by iso-myosmine, as assessed by flow cytometry. Interestingly, the subset of thyroidal CD4+Foxp3+ regulatory T cells expanded with iso-myosmine. Serum thyroglobulin antibodies decreased in the iso-myosmine group, reaching a nadir after 6 weeks. Total T4 and T3 did not differ among the four experimental groups, whereas TSH increased upon iodine supplementation but remained in the normal range with iso-myosmine. Overall, the study suggests that iso-myosmine ameliorates thyroiditis acting on specific lymphoid subsets. Further studies, also extending to other autoimmune diseases, will confirm the potential clinical utility of iso-myosmine as a novel immunometabolic regulator.
Autoimmunity Thursday Poster Clinical
Intravenous methylprednisolone (IVMP) is recommended as the first-line treatment for moderate-to-severe and active thyroid-associated ophthalmopathy (TAO). However, not all patients are responsive to IVMP, and the factors associated with the therapeutic efficacy remain inadequately understood. The aim of this study was to identify potential predictors and establish a multivariable predictive model for the efficacy of IVMP therapy. A total of 302 consecutive patients diagnosed with moderate-to-severe and active TAO, who underwent the full course of IVMP therapy were included in this single-center retrospective study. Participants were sequentially divided into the training set (n = 200) and the validation set (n = 102). Multivariate logistic regression analysis was used to identify the independent predictors and establish the predictive model. Five independent predictors were identified and included in the model. In addition to pretreatment clinical activity score (OR = 4.241, P < 0.001), dysthyroidism during treatment (OR = 0.035, P < 0.001), pretreatment anti-TSH-receptor antibody levels (OR = 0.085, P = 0.001) and duration of eye symptoms (OR = 0.848, P = 0.011), a significant relationship was found between the efficacy of IVMP therapy and pretreatment triglyceride levels (OR = 0.067, P = 0.001). The predictive model showed good calibration and excellent discrimination for the efficacy of IVMP therapy, with areas under ROC curves of 0.947 (P < 0.001) and 0.909 (P < 0.001) in the training and validation sets, respectively.
Pretreatment triglyceride levels are associated with the therapeutic efficacy. The multivariable predictive model may serve as a useful tool for determining the indication and prognosis of IVMP therapy. Moreover, several suggestions regarding the modifiable predictors have been made in the management of TAO patients to improve the therapeutic efficacy: early diagnosis and treatment (within 15 months); prompt restoration and maintenance of euthyroidism, especially meticulous control of TSH levels (≤ 5 μIU/mL); regular monitoring and control of triglyceride levels (<150 mg/dL).
Disorders of Thyroid Function Thursday Poster Basic
Thyroid disease is the most common endocrine disease whose incidence has increased rapidly in in recent decades. Thyroid dysfunction has been demonstrated to be closely associated with cardiovascular diseases, metabolic syndrome and other diseases. Chondroitin Sulfate Proteoglycan 4 (CSPG4) also called NG2 (Neuron-glial antigen 2), plays a critical role in trauma, inflammation and tumor, however, the role of NG2 in thyroid has not been thoroughly revealed. To explore the role of NG2 in regulating thyroid function and metabolic index, we generated thyroid-specific NG2 knockout (thyroid-NG2 KO) mice and NG2-null thyroid immortalized cells. qRT-PCR was performed for mRNA assay while western blot, ELISA and immunohistochemical staining were used for protein level analysis. For histology, H&E staining under optical microscope and ultrastructure observation were performed. In this study, we found that thyroid-NG2 KO mice showed lower thyroid hormone, higher body weight, more white adipose tissue accumulation, elevated blood lipids and impaired insulin sensitivity. Our data also illustrated the possible mechanism which showed that knock-down of NG2 attenuated the activities of PI3K/AKT and MAPK/ERK signaling pathways, thus down-regulated cMyc. As a core regulator of microRNA network, cMyc inhibited miR-142 and miR-30c, which weaken TSHR at post-transcriptional levels. Owing to the reduction of TSH/cAMP, PI3K/AKT and MAPK/ERK signal activities, thyroid and metabolism showed depressed function, which may explain the metabolic disorders in Ng2-deficient mice. In a word, this study explored the role and mechanism of NG2 in maintaining normal thyroid function through a series of in vitro and in vivo experiments. Firstly, thyroid-NG2 KO mice developed thyroid dysfunctions through depressed TSHR, TSH/cAMP, PI3K/AKT and MAPK/ERK signaling pathways, thereby offering a molecular basis for pathogenesis of thyroid diseases. Interestingly, Ng2 ablation in thyroid also resulted in various metabolic disorders which can be explained by thyroid dysfunctions, adding a novel thought to Ng2 and TSHR related diseases, metabolic syndrome and other metabolic diseases.
Disorders of Thyroid Function Thursday Poster Clinical
Routine TSH measurement in hospitalized patients is generally not recommended because sick euthyroid physiology can complicate its interpretation. However, TSH is commonly measured in hospitalized patients without preexisting thyroid disorders. In order to understand the impact of TSH testing on inpatient patient care we retrospectively identified patients with at least one TSH measurement during hospitalization and analyzed the reasons for its measurement and its ultimate utility in their care.
Retrospectrive identificartion patients with at least one TSH measurement during hospitalization via review of electronic medical records.
196 patients had at least one TSH measurement in May 2017 after excluding those being treated for hyper- or hypothyroidism. Abnormal TSH values were found in 16.8% (33), and 70.4% (138) had more than one TSH measurement in the preceding year. Retesting was common with repeat measures being done 2, 3, 4, 5, and 6 times per year in 15.3%, 24.4%, 13.2%, 13.7%, and 3% respectively. 54 patients (27.5%) had sepsis, 30 patients (15.3%) had falls as the reason for testing, and 42 patients (21.4%) had a cardiac cause for admission to the hospital. Interestingly, none of the patients were on amiodarone or steroids. Ten (5%) patients had diagnoses of anxiety or mood disorder as the cause for testing. Notably, no patient had any change in management based on the TSH values obtained while hospitalized. Despite an absence of recommendations, sepsis and falls in the elderly accounted for 50% of TSH testing in hospitalized patients in our study.
TSH measurement is not useful in the inpatient setting unless specific clinical circumstances can guide its use. The majority of inpatient TSH testing appears to raise costs without benefit, but it may be useful to study when its measurement could be helpful during hospitalization, and further it may be appropriate to develop specific guidelines to foster a practical approach for thyroid function testing in hospitalized patients.
Disorders of Thyroid Function Thursday Poster Clinical
The effectiveness of levothyroxine (L-T4) in soft gel capsule formulation in patients recently subjected to total thyroidectomy is not yet well known. Our aim is to study the efficacy of L-T4 in soft gel capsule formulation in comparison to L-T4 tablets, in patients recently submitted to total thyroidectomy, with no malabsorption or drug interference issues.
Two hundred patients were included in the study of which 100 received soft gel capsule L-T4 formulation, while 100 took L-T4 tablets using the same dosage (1.5 mcg/kg/day). Treatments started the day after surgery, with L-T4 administered 30 min before breakfast. At week 6 (1st control), and then at week 12 (2nd control) for both the groups of patients thyrotropic hormone (TSH), free thyroxine (FT4), and free triiodothyronine (FT3) were evaluated.
TSH values were significantly lower in the soft gel capsule L-T4 group, with respect to the tablet L-T4 group, in both the first (P < 0.05) and the second control (P < 0.01), while no significant differences were observed for FT4 and FT3 levels. The prevalence of patients in the hypothyroid range (TSH >3.6 mcU/ml) was higher in the L-T4 tablet group in comparison to the soft gel capsule L-T4 group.
A better efficacy of soft gel capsule L-T4 (versus L-T4 tablets) was observed in controlling TSH levels in patients previously undergone to total thyroidectomy for thyroid cancer without issues of malabsorption, gastric disorders, or drug interference.
Iodine Uptake & Metabolism Thursday Poster Clinical
Thyroid dysfunction is associated with negative neonatal and obstetric outcomes. There are large differences in thyroid function reference intervals between different populations. These differences can be explained by population specific factors, like iodine status. We estimate thyroid hormone reference ranges in patients with optimal urinary iodine (UI) and calculate thyroid function in this population. This is a prospective observational study of healthy Chilean women in their first prenatal visit before week 14. TSH, total T4, free T4 (FT4), antithyroid peroxidase antibodies (TPOAb) and UI from spot sample were measured. Reference ranges for TSH were calculated in woman with adequate and more than adequate UI.1022 first trimester pregnant women were selected. UI was performed in 302 women randomly selected. Median UI was 239 ug/L, 27,8% of patients had insufficient UI, 24,7% adequate UI, 41% more than adequate UI and 6,4% of these women had excess UI. Reference ranges of TSH were calculated in 162 women with adequate and more than adequate UI and negative TPOAb. Percentile 97,5 for TSH was 5,0 mIU/L. We apply the cut off value of TSH calculated in our population for diagnosis in the 1022 women and the prevalence of clinical and subclinical hypothyroidism was 1,9%, and 5,4% respectively. TPOAb prevalence was significantly higher in women with TSH above 5,0. Insufficiency and excess iodine coexist in fortified population as we report in Chilean pregnant women. Our TSH cut off point and the prevalence of hypothyroidism in our first trimester pregnant population are higher than described in the literature. TPOAb prevalence support our TSH cut off point. While there are multiple factors involved, it is likely that iodine exposure of our population could explain part of this higher prevalence of hypothyroidism.
Thyroid Cancer Thursday Poster Basic
Distant metastases are the primary cause of tumor-related mortality in patients with solid tumors. We previously identified Regulator of Calcineurin (RCAN)1.4 as a new metastasis suppressor in thyroid cancer and defined a mechanistic role for the transcription factor NFE2L3 (Nrf3) in its function in vitro and in immunosuppressed mouse models. The goal of this work is to characterize the mechanism of RCAN1.4/Nrf3 signaling axis in metastasis suppression in immune-competent systems. We generated RCAN1.4 knockout mice and crossed them with a thyroid-specific BRAFV600E -inducible mouse in a cancer-resistant C57/BL6J-mix background and evaluated NRF3 transcriptional regulation of IL8 in vitro. Tg-rTTA;tetO-BRAFV600E;Rcan1.4+/- (het) and Tg-rTTA;tetO-BRAFV600E;Rcan1.4-/- mice (KO) (n = 27) developed higher grade tumors than Tg-rTTA;tetO-BRAFV600E;Rcan1.4+/+ (WT) littermates (n = 15, Fisher's exact p = 0.016) after 1 week of doxycycline treatment. Further, tumors from het and KO mice displayed 28-fold increase in proliferation (%KI67+ cells, p = 0.04) and 7-fold increase in T-lymphocytic infiltration (%CD3+ cells, p = 0.08).
In human thyroid cancer cells, we previously demonstrated that RCAN1.4 loss is associated with Nrf3 overexpression. In this work, we observed increased IL8 expression and release upon RCAN1.4 loss from thyroid cancer cells. Further, we identified a putative MARE binding domain (Nrf family binding sequence) upstream of the IL8 promoter. IL8-promoter luciferase assay demonstrated robust activation following Nrf3 transfection vs controls. ChIP-PCR experiments are ongoing to confirm binding. Finally, we identified that IL8 and NRF3 show positive correlation (r2 = 0.314, p<e-12) in the thyroid cancer TCGA dataset, with BRAF-mutant tumors displaying higher levels of both genes. RCAN1.4 metastasis suppressor loss activates a pro-tumorigenic program in mice with thyroid-specific induction of BRAFV600E accompanied by increased proliferation and immune cell infiltration. Nrf3, a functional regulator of RCAN1.4 loss, likely directly enhances IL8 expression. Further studies are required to clarify the functional links between the RCAN1.4/Nrf3 signaling pathway, immune activation, proliferation, and cancer progression.
Thyroid Cancer Thursday Poster Basic
LncRNA (long non-coding RNA) may play essential roles in thyroid cancer. In our previous study, YAP1 (Yes-associated protein 1) stimulates proliferation of PTC (papillary thyroid cancer), and regulates cell cycle, migration and invasion, but it is unclear that if lncRNA is involved in this progress. We also found that in 16 lncRNAs which might interact with YAP1, lncPTC1 got a higher expression level in PTC. Our study was aimed to figure out whether lncPTC1 is associated with PTC and YAP1 related pathway. We used RNA immunoprecipitation-seq (RIP-seq) to identify the potential lncRNAs that may interact with YAP1. Quantitative real time polymerase chain reaction (qRT-PCR) was performed in 70 PTC tissues and their paired normal thyroid tissues to dig out relationship among expression level of lncRNAs and clinical pathological parameters. RIP and RNA pull-down were applied to figure out YAP1 interacting lncRNA. The proliferation, migration and apoptosis condition were analyzed by cell counting-8 (CCK8), trans-well, clone formation and flow cytometry. Here we identified YAP1 related lncRNAs in the tumorigenesis of PTC and fingered out the underlying mechanism. We found that among 16 lncRNAs which might interact with YAP1, lncPTC1 expressed higher in PTC tissues than their paired normal thyroid tissues. Its over-expression related to larger tumor size, lymph node metastasis and advanced TNM stage. RIP and RNA pull-down data showed that lncPTC1 interacted with YAP1. The results of CCK8, trans-well, clone formation and flow cytometry indicated that lncPTC1 could inhibit cell proliferation, migration and induce cell apoptosis. Our study suggests that YAP1 interacting lncPTC1 is involved in tumorigenesis of PTC, indicating that lncPTC1 may be a potential biomarker and therapeutic target of PTC.
Thyroid Cancer Thursday Poster Case Report
Prostate-specific membrane antigen (PSMA) has been used as a theranostic target for prostate cancer. Despite its name, its overexpression has been reported on the neovasculature of variety of non-prostate cancer. Some studies have reported its expression in differentiated thyroid cancer (DTC) and metastatic DTC in vivo by PSMA PET/CT. While, the expression level of PSMA in radioiodine refractory thyroid cancer (RAIR-DTC) is still unknown. As the therapeutic approach for RAIR-DTC is so limited, so we want to evaluated the expression level of PSMA in RAIR-DTC and explore whether PSMA can be a new therapeutic target for RAIR-DTC. A 61-year-old woman diagnosed as follicular thyroid cancer (FTC), staged as T4aN0M1 after total thyroidectomy in 2012. As her preoperative chest CT showed highly suspicious pulmonary metastases, subsequent three times radioiodine (RAI) therapy was conducted, with RAI doses 2.22, 7.4GBq and 7.4GBq in 2 years after surgery. As RAI was only concentrated in a part of lung metastatic lesions but not in others, she was classified as RAIR-DTC. RAI therapy was stopped and instead by intensive follow-up for her. In 2016, serial chest CT has demonstrated the progression of pulmonary metastases, and new local recurrent lesions were detected by ultrasound examination. On 7 December, 2016, secondary surgeon was conducted for the local recurrence. In addition, multikinase inhibitor was recommended for her. She participated in a phase II clinical trial of Donafenib for RAIR-DTC. After the 48 weeks' treatment of Donafenib 200mg, qd, she was classified as progressive disease. We hypothesized that PSMA may express in RAIR-DTC as well, which would provide a potential new therapeutic option for the RAIR-DTC who failed in multikinase inhibitor therapy. So a 68Ga-PSMA-617 PET/CT was conducted for this patient. The hypermetabolic metastases from RAIR-DTC in thyroid bed, lungs, bones, soft tissues and inferior vena cava showed strong accumulation of PSMA (highest SUVmax >20.0), which is the evidence of PSMA expression in vivo. PSMA express in RAIR-DTC, which may lead PSMA-targeted radionuclide therapy to be a novel therapy for RAIR-DTC, who failed in the multikinase inhibitor therapy.
Thyroid Cancer Thursday Poster Clinical
The aim of this study was to assess the ultrasound diagnostic performance of three methods—the ACR TI-RADS, the Kwak TI-RADS, and the 2015 ATA Guidelines for risk stratification—on thyroid nodules greater than 4cm. This study included 279 thyroid nodules greater than 4cm in 267 patients who underwent thyroidectomy at the Peking Union Medical College Hospital between January 2010 and January 2017. The patients were divided into two groups according to the pathologic results: those with malignant nodules and those with benign ones. The ACR and Kwak TI-RADS and the 2015 ATA Guidelines were used to evaluate the nodules. The sensitivity, specificity, accuracy and Area Under Curve (AUC) of all three methods were calculated. Of the 279 thyroid nodules greater than 4cm, 229 (82.1%) were benign and 50 (17.9%) were malignant. The malignancy rates of the five ACR TI-RADS categories (TR1 to TR5) were found to be 0, 3.3%, 16.2%, 52.9% and 84.6%, respectively. The malignancy rates of the six Kwak TI-RADS categories (2 to 5) were found to be 0, 5.1%, 16.7%, 43.1%, 91.7% and 0, respectively. The malignancy rates of the five ATA stratifications (benign to high suspicion) were found to be 0, 0, 9.2%, 34.1%, and 94.7%, respectively. Thyroid nodules that were greater than 4cm and were classified into Kwak TI-RADS categories of 3, 4a, 4b, 4c and ATA intermediate suspicion showed a higher, in some cases much higher, malignancy rate. The results of the sensitivity, specificity and accuracy of the three methods were consistent with those established in the existing literature: for the ACR TI-RADS they were 58.0%, 92.0% and 86.0%, respectively, and for the Kwak TI-RADS and ATA Guidelines they were 66.0%, 86.9% and 83.2%, respectively. The sensitivity, specificity and accuracy showed that the ACR and Kwak TI-RADS and ATA Guidelines have good performances in evaluating thyroid nodules greater than 4cm. The classification rating for malignancy rates of nodules greater than 4cm classified into Kwak TI-RADS 3, 4a, 4b, 4c should be raised by a level.
Thyroid Cancer Thursday Poster Clinical
Recently the 7th edition of the AJCC staging system for differentiated thyroid cancer (DTC) has been replaced by the 8th edition. Some changes were made objecting the appropriate staging of the vast majority of DTC patients as being at low risk for dying from the disease. The 8th edition downstaged a lot of patients changing the cut off age from 45 years at diagnosis to 55 years and by removing lymph node metastasis and minimal extrathyroidal extension (METE) of the stage III, thus minimizing the significance of METE. Therefore, this study aims to evaluate the impact of this new classification in a cohort of 505 differentiated thyroid cancer patients whose tumors present METE. This research was carried out using the database of a public institution. The 7th and 8th editions of the TNM staging system were applied to 5344 DTC patients, underwent total thyroidectomy, but just those with METE were selected (n = 505). Subsequently, the main changes between the two editions were analyzed. Patients with missing data on pathologic T, N, M stages were excluded. All statistical analyses were performed using SPSS 13.0 software. Of the 505 patients, 84% were female and the median age was 48 years. 299 patients (59.2%) were downstaged from the 7th to the 8th edition. In recently published studies, about 23% of the patients were downgraded in the SEER, while 24% were downgraded in the NCDB, but different from our study, they did not analyze just patients with METE. Similarly to these studies, all stage III patients in the 7th edition were downgraded (81,3% for stage I and 18,8% for stage II). In the 7th edition, there were fewer stage I patients than the 8th (35% vs 76,6%, respectively) and more stage IV (11,7% vs 3%). Of the 505 patients analyzed, 129 (25,5%) were in the age range in which the cut off was changed (45-54 years). Of these patients, 92.2% were reclassified for stage I and 7.8% for stage II. A significant number of patients with METE were downgraded with the 8th edition changes. That updates could improve the accuracy of the staging system for predicting mortality with significant impact on both initial therapeutic decision making and on follow up in order to reduce over-treatment.
Thyroid Cancer Thursday Poster Clinical
Anaplastic thyroid carcinoma (ATC) is a highly aggressive malignancy characterized by local invasion and propensity for distant metastases. The majority of patients present with inoperable disease, often with impending airway obstruction and significant dysphagia. BRAFV600E mutation is detected in 25-45% of ATCs and can be targeted with dabrafenib and trametinib, which has recently received FDA approval.
Retrospective case series. We report our institutional experience with six consecutive ATC patients with BRAFV600E mutation who underwent surgical resection following treatment with neoadjuvant dabrafenib and trametinib with or without pembrolizumab. Surgical resection was followed by adjuvant chemoradiation. All six patients initially presented with unresectable T4b disease. Significant treatment response was observed after dabrafenib/trametinib initiation within weeks, decreasing tumor burden and disease surrounding critical structures, allowing for surgical resection. Three out of six patients also received pembrolizumab in addition to BRAF/MEK inhibitors. R0 or R1 resection was achieved in all patients. Pathologic analyses of resected specimens showed high pathologic response rates with significantly decreased ATC viability (<30% in all cases) and residual well-differentiated, papillary thyroid carcinoma, components. In 5 out of 6 patients, tracheostomy was avoided. All 3 patients who developed progressive disease had delay or failure to resume targeted therapy after completion of postoperative radiotherapy. Two patients died of distant metastasis at 6 and 13 months from diagnosis but remained without locoregional disease. The remaining four patients are currently without locoregional or distant disease with continuing follow-up. At 12 months, 80% of the patients were alive. In a small cohort of unresectable BRAFV600E-mutated ATC, utilization of dabrafenib with trametinib in a neoadjuvant setting can decrease locoregional disease burden to facilitate surgical resection, decrease locoregional morbidity, and improve locoregional control. We identified high pathologic response rates, durable locoregional control, and decreased need for tracheostomy.
Thyroid Cancer Thursday Poster Clinical
Targeted therapy has been adopted to treat radioiodine-refractory differentiated thyroid cancer (RR-DTC) and other cancers, but the most appropriate response criteria have not been determined. The aim of this study was to evaluate the role of 18F-FDG PET/CT in the monitoring of response to sorafenib treatment in RR-DTC patients, comparing Response Evaluation Criteria in Solid Tumors (RECIST) with the European Organization for Research and Treatment of Cancer (EORTC) criteria. A single-center retrospective analysis was conducted in 14 RR-DTC patients treated with sorafenib from December 2011 to December 2018. The percentage changes in the sum of target lesion diameters and the sum of maximum standardized uptake values (ΣSUVmax) before and at nearly 3 months after the initiation of sorafenib treatment were compared. Morphologic and metabolic responses were evaluated using CT (RECIST 1.1) and 18F-FDG PET (EORTC criteria), respectively. The differences in progression-free survival (PFS) between response categories were evaluated. The correlation between PFS and either morphologic or metabolic response was estimated. There was an agreement between the RECIST 1.1 and EORTC criteria in 10 of the 14 patients (P = 0.424). The remaining 4 patients with SD included 2 patients with PMR and 2 patients with PMD. Differences in PFS among different response categories according to RECIST 1.1 (P = 0.003) were statistically significant. Well correlation between PFS and EORTC response (r = 0.816; P = 0.0004) was reached, which is better than PFS and RECIST 1.1 response (r = 0.741; P = 0.002). Differences in PFS among different response categories according to either RECIST 1.1 (P = 0.003) or EORTC criteria (P = 0.003) were statistically significant. Correlations were found between PFS and either morphologic (r = 0.741; P = 0.002) or metabolic (r = 0.816; P = 0.0004) response criteria.18F-FDG PET/CT imaging is of value in the monitoring of response to sorafenib in RR-DTC patients. Although RECIST 1.1 and EORTC criteria agree in 71.4% patients, PET-based metabolic response criteria seem to be more accurate in predicting therapeutic outcome and may be more suitable than morphologic response criteria for the evaluation of response to targeted therapy.
Thyroid Cancer Thursday Poster Clinical
There is undeniable association of thyroid carcinoma with female gender but few studies on estrogen receptors (ER) and human epidermal growth factor receptor 2 (HER 2) receptors in thyroid carcinoma. The primary aim of this study was to determine the incidence of Estrogen receptor α (ER α), Estrogen receptor β (ER β) and HER 2 receptors expression in various subtypes of thyroid carcinoma of follicular origin and the secondary aim was to correlate the expression with various clinico-pathologic prognostic factors. Immunohistochemistry analysis was performed on archival paraffin-embedded tissue sections (1991-2016). ER α, ER β and HER 2 receptors expression were correlated with age, gender, tumor size, multi-centricity, extra-thyroidal invasion, lymph nodal status, distant metastases, disease recurrence and overall survival (OS).124 papillary thyroid carcinoma (PTC), 108 follicular thyroid carcinoma (FTC) and 36 poorly differentiated thyroid carcinoma (PDTC) specimens were included in the study. Incidences of ER α, ER β and HER 2 receptors were, 8.1 Vs 16.3 Vs 13.9% (p = 0.15); 26.6 Vs 11.5 Vs 36.1% (p = 0.002); and 12.9 Vs 2.9 Vs nil % (p = 0.003) in PTC, FTC, and PDTC respectively. There was no correlation between ER α, ER β and HER 2 receptors expression (p = 0.64, 0.49, & 1.00). On univariate analysis ER α expression was significant correlated with metastases (p = 0.040), and ER β beta with lymph nodal involvement (p = 0.014). HER 2 expression was associated with presence (p = 0.029) and ER β beta with absence (p = 0.026) of poorly differentiated areas in tumor. On multivariate analysis only ER α expression was associated with metastases (0.038). OS was not affected by ER α ER β and HER 2 receptors expression. ER α, ER β and HER 2 receptors expression seems to have differential expression and prognostic significance in various thyroid carcinoma subtypes. Their therapeutic implications need to be studied further.
Thyroid Cancer Thursday Poster Clinical
BRAFV600E mutation is the most common genetic event in papillary thyroid cancer (PTC), yet its clinical value of BRAFV600E testing in fine-needle aspiration (FNA) specimens remains uncertain. Our study aimed to confirm whether BRAFV600E mutation testing are useful in confirming diagnoses for thyroid nodules and to figure out potential roles of BRAFV600E mutation in evaluating disease status before surgery. We retrospectively searched for patients with suspicious nodules on ultrasound (US) who accepted US-FNA at Fudan University Shanghai Cancer Center (FUSCC) from May 2016 to March 2018. Patients who met these criteria were included in our study: (1) with cytologic outcomes, (2) obtaining BRAF mutation testing results, (3) accepting surgeries after FNA, (4) availability of adequate medical records. Histopathological results are the only standard to make the final diagnosis.1144 patients with average age of 44.4 ± 11.2 years were enrolled in our study. Of the 1144 patients, the cytological results were nondiagnostic/unsatisfactory (ND/UNS) in 49 (4.3%) cases, benign in 38 (3.3%), atypia/follicular lesion of undetermined significance (AUS/FLUS) in 82 (7.2%), follicular neoplasm/suspicious for follicular neoplasm (FN/SFN) in 4 (0.3%), suspicious for malignancy (SM) in 157 (13.7%), and malignant in 814 (71.2%). BRAFV600E mutation was found in 82.2% of all of them (940/1144). The BRAFV600E mutation testing screens out 9 cases (31.0%) from the 29 patients with diagnoses of ND/UNS at cytologic readings, who were finally diagnosed with PTC by histopathology. Of the 243 cases with unsure diagnoses of cytology, 168 cases harbored BRAFV600E mutation were all confirmed to be malignant. Though BRAFV600E was related to advanced T stage (OR = 1.690, 95%CI = 0.992-2.878, p = 0.042), N stage (OR = 1.594, 95%CI = 1.161-2.189, p = 0.003) and extrathyroidal extension (ETE, OR = 1.873, 95%CI = 1.145-3.063, p = 0.008), it failed to predict for central lymph node metastasis (AUC = 53.6%, area under the ROC curve; ROC, receiver operating characteristic) and ETE (AUC = 54.2%) before surgery. Our study indicates that BRAFV600E mutation testing in FNA samples increases diagnostic accuracy of thyroid nodules, but fails to assist in evaluating disease status.
Thyroid Cancer Thursday Poster Clinical
Acromegaly is a rare disorder caused by excessive production of growth hormone and insulin-like growth factor 1. While there is up to a 2-fold increased prevalence of thyroid nodules in acromegalic patients compared to the general population, the incidence of thyroid cancer in this patient population varies from 1.6-10.6% in several European studies. The 2015 American Thyroid Association guidelines for thyroid nodules and thyroid cancer do not contain recommendations for the screening of thyroid nodules among patients with acromegaly, while the 2014 Endocrine Society guidelines for acromegaly suggest a thyroid ultrasound among such patients with a palpable nodule.
Thyroid Cancer Thursday Poster Translational
Medullary Thyroid Cancer (MTC) arises from thyroid parafollicular C cells, which are embyrologically distinct from thyroid follicular cells. MTC accounts for 5% of all cancers arising in the thyroid and is hereditary in approximately 25% of cases. The most common mutations in papillary thyroid carcinoma appear to be the BRAF V600E mutation, followed by RET-PTC fusions. The most common mutations in MTC are point mutations in RET which confer a gain of function to this receptor tyrosine kinase. In the past 10 years, screening chips for multiple oncogenes have been growing in use. We herein report a case of a 66 year old African American female with an incidentally discovered 1.3 cm thyroid nodule. Cytological exam revealed features of MTC and was positive for calcitonin and CEA by immunohistochemistry. She has no family history of thyroid cancer and no other features of MEN2. Serum calcitonin was elevated at 257 pg/ml. Serum DNA analysis was negative for RET oncogene germline mutation. Imaging studies with neck and chest CT scans, and MRI of liver were negative. Following a total thyroidectomy, a multifocal MTC with extrathyroidal extension and 6/10 positive lymph nodes was reported. One year later, she remains asymptomatic; serum calcitonin level is 114 pg/ml with a normal CEA level, and no evidence of residual tumor by neck ultrasound or CT scan. A 50-oncogene NexGen somatic mutation analysis was negative for mutations, including RET and RAS, but positive for a BRAF (V600E) mutation. To confirm this unusual oncogene pattern, we performed an independent analysis of BRAF using a single nucleotide variant genotyping mass spec analysis (Sequenom, Agena) and confirmed that the V600E mutation was present at a low allele frequency (5-10%) indicating tumor heterogeneity or low tumor burden within the sample. The vast majority of studies analyzing somatic mutations in MTC continue to demonstrate that mutations other than RET and RAS are very rare or absent. Our patient had pathological features of invasive MTC without concurrent PTC, with no RET mutation but a common BRAF mutation.
Thyroid Cancer Thursday Poster Translational
DICER1 mutations in the RNase IIIb domain have been reported as potential driver events in thyroid tumors, especially in follicular-patterned neoplasms. However, the clinical interpretation of these mutations is controversial because they have been found in both benign and malignant lesions. Moreover, DICER1 mutations have been reported as germline or somatic. In the present study we investigated how DICER1 mutations affect miRNA processing in thyroid tumors. Forty-one thyroid lesions, including 19 follicular adenomas (FAs) and 22 follicular variant of papillary thyroid carcinomas (FVPTCs) were tested for the presence of mutations in the RNase IIIb domain of DICER1, BRAF and the RAS genes using both tumor and paired contralateral normal tissue. The miRNA expression profiling was also performed by the nCounter human v3 miRNA expression assay (NanoString Technologies). After data normalization, unsupervised hierarchical clustering using Pearson's correlation was carried out. 5p and 3p miRNA percentages were defined as the proportion of cumulative 5p and 3p miRNAs on the total respectively. Overall, 8 NRAS, 4 HRAS and 2 DICER1 mutations were found. All but one RAS mutations (one NRAS p.Q61R) were present in FVPTCs. The two DICER1 mutations (one p.D1810V and one p.E1813K) were found in heterozygosis in FAs. All mutations were somatic. Clustering analysis showed that the miRNA profile of the two DICER1 mutant FAs was similar and very different from all the other lesions. All samples had a predominance of 5p miRNAs, except for the two DICER1 mutant FAs. Herein, we confirmed that DICER1 mutations are mutually exclusive with the most common alterations in thyroid tumors. Although they are not specific markers for malignancy, FAs harboring somatic heterozygous mutation in the DICER1 RNase IIIb domain have a consistent loss of 5p miRNAs.
Further studies investigating the evolution of DICER1 mutant lesions are warranted to provide useful information in the clinical decision-making.
Thyroid Hormone Metabolism & Regulation Thursday Poster Basic
The T4 to T3 converting enzyme type 2 iodothyronine-deiodinase (D2) is required for normal differentiation of skeletal muscle progenitors (SMPs). Our previous studies implicate a role for D2 in skeletal muscle SMPs in myogenic fusion, as loss of D2 results in increased fiber cross-sectional area, and a higher number of nuclei per myotube in vitro. D2 is also found in pro-myogenic fibro adipogenic progenitors (FAPs) in the muscle stem cell niche, and this cell type is critical for skeletal muscle regeneration. However, the extent to which D2 activity in this cell type influences muscle fusion is unknown. We hypothesized that loss of D2 in either the SMPs themselves and/or the FAPs leads to increased myoblast fusion of D2KO SMPs. The effect of D2 loss from either FAPs or SMPs on myogenic fusion was studied using co-cultures of FACS purified SMPs +/- FAPs from WT and D2KO mice. To further define molecular mechanisms we disrupted the Dio2 gene in C2C12 cells using CRISPR/Cas9 (D2KO C2C12 cells), which were subsequently differentiated via serum withdrawal. RNA was collected during differentiation and the expression of fusogenic factors analyzed via qPCR. Co-culture experiments revealed that both WT and D2KO-derived FAPs potentiated WT SMP myogenic differentiation and fusion to a similar extent. In contrast, FAP addition did not significantly enhance D2KO SMP differentiation, while D2KO SMP fusion was also increased by the presence of WT and D2KO FAPs to a greater extent than WT SMPs plus FAPs. In vitro, gene expression of the fusogen protein myomaker was significantly higher in D2KO C2C12 cells on day 3 of differentiation compared to WT. Autocrine production of IL-4 plays a role in potentiating myoblast fusion, however IL-4 production was very low in the C2C12 cells and IL-4 receptor expression was significantly lower in D2KO SMPs, suggesting that this pathway is not relevant in our system. Taken together, our data highlights the importance of SMP D2 activity in myoblast fusion, and further suggests the increased fusion of D2KO SMPs is cell autonomous and may be the result of changes in expression of fusogenic factors such as myomaker.
Thyroid Imaging Thursday Poster Clinical
Whether to have surgery on PTMC has caused much discussion. Some have recommended surgery on PTMC with extrathyroidal extension. But the efficiency of the conventional two-dimensional ultrasound (2D-US) in assessing ETE has shown great variation in different studies. The aim of the present study was to evaluate the efficiency of OmniView of three-dimensional ultrasound (3D-OmniView) in assessing extrathyroidal extension (ETE) of papillary thyroid microcarcinoma (PTMC) by comparing it with the efficiency of two-dimensional ultrasound (2D-US). From February 2016 to January 2018, we enrolled 274 thyroid nodules which were close to the capsule of the thyroid in 168 preoperative patients at our center. Among the 274 nodules, 98 with papillary thyroid carcinoma (PTC) and in 80 patients were selected and included in this study. Both 2D-US and 3D-OmniView were used to evaluate ETE, which was found to be present in 56.1% of the 98 nodules. The comparative result of the sensitivity of 2D-US and 3D-OmniView in evaluating ETE of PTMC was 36.4% vs 69.1%, and that of the specificity was 81.4% vs 83.7%. This study shows that 3D-OmniView is better than 2D-US in diagnosing ETE of PTMC.
Thyroid Imaging Thursday Poster Clinical
For three-dimensional ultrasound (3D-US) presengt a better spatial structure for interested lesions than two-dimensional ultrasound (2D-US), and varies standards were recommended to evaluate thyroid nodules. So we intended to evaluate thyroid nodules by the standard of TI-RADS of American College of Radiology (ACR) and 2015 ATA guidelines based on 3D-US characteristics of thyroid nodule, and compare with 2D-US.235 thyroid nodules in 159 patients were prospectively included before thyroidectomy at our center from February 2016 to January 2018. The demographic data and general ultrasonic features of the patients were collected. 2D-US and 3D-US were used respectively to evaluate echogenicity, composition, shape, margin, calcifications and extrathyroidal extension of the thyroid nodules. Finally, the nodules were classified by ATA guidelines and ACR TI-RADS grading standard respectively. Among the 235 nodules, 62 were benign and 173 were malignant. The malignant percentage of 3D-US with unclear boundary, irregular margin and extrathyroidal extension was higher than that of 2D-US (76.3% vs 74.6%; 91.3% vs 86.7%; 67.6% vs 39.9%), and the malignant percentage of punctate echo was low (43.9% vs 52.0%). Compared with 2D-US, 3D-US increased the malignant percentage of high suspicion in ATA guidelines and ACR TI-RADS TR5 (97.1% vs 98.2%; 90. 9% vs 91.7%), and reduced the malignant percentage of Intermediate suspicion in ATA guidelines and ACR TI-RADS TR4 (45.5% vs 37.5%; 72.7% vs 59.4%). ATA guidelines grading of thyroid nodules in 3D-US showed a slight increase in sensitivity (97.1% vs 98.2%)and a slight decrease in specificity (75.0% vs 72.9%). The sensitivity of ACR TI-RADS grading (86.1% vs 89.0%) and specificity (75.8% vs 79.0%) were slightly elevated.3D-US is different from 2D-US in identifying some ultrasonic features of thyroid nodules, and can slightly improve the diagnostic efficiency of ACR TI-RADS classification and partial diagnostic efficiency index of ATA guidelines for thyroid nodules.
Thyroid Imaging Thursday Poster Clinical
Sonographic risk stratification and molecular testing are independently used to assess malignancy risk in cytologically indeterminate thyroid nodules. This study aimed to determine whether ultrasound characteristics and molecular testing have synergistic diagnostic utility for indeterminate nodules. Cytologically indeterminate (Bethesda 3 and 4) thyroid nodules within UCLA Health in 2012-2016 were studied. All had reflexively undergone Afirma Gene Expression Classifier (GEC) testing. In this retrospective analysis, four radiologists performed blinded reviews to assign the corresponding archived ultrasounds (US) to an American Thyroid Association (ATA) sonographic risk category for malignancy. Two radiologists independently reviewed each US for concordance. Outcomes of surgically resected nodules were determined via histopathology, and unresected nodules with a benign GEC result were considered benign if stable in size on US >1 year after biopsy. Of 144 nodules (mean size 2.6 cm) from 136 patients (83% female, mean age 50 years), 33% were malignant on histopathology. Concordance for paired US assessments was 85%; 10% of nodules were ATA high suspicion, 40% intermediate, and 50% low or very low suspicion. Almost all high suspicion nodules (92%) had a suspicious GEC result, compared to 65% of intermediate and 56% of low or very low suspicion nodules. Positive predictive value of GEC in high (55%), intermediate (41%), and low or very low suspicion nodules (54%) did not vary significantly. GEC had high overall sensitivity (98%) and negative predictive value (98%). The ATA high suspicion category had higher specificity compared to a suspicious GEC result (93% vs. 51%, p < 0.0001). A concurrent suspicious GEC result and ATA high suspicion category did not significantly improve the specificity of the ATA high suspicion category alone (94% vs. 93%). ATA ultrasound risk category did not significantly affect GEC's positive predictive value for cytologically indeterminate thyroid nodules. Given the high specificity of the ATA high suspicion category and high likelihood of a suspicious GEC result, the clinical utility and cost effectiveness of molecular testing may be limited for nodules in this category.
Thyroid Nodules & Goiter Thursday Poster Clinical
The Bethesda System for Reporting Thyroid Cytopathology (BSRTC) was developed to regulate the report of Thyroid Fine Needle Aspiration (FNA). Since its implementation, it has proven to be a valid and reliable method. Each institution must review its internal malignancy rates, as the rate of each individual BSRTC category may vary among institutions. The objective of this study was to to determine the frequency of the BSRTC categories in our institution and to establish malignancy rates in each category.
A total of 766 thyroid nodules FNA cytology processed at James A. Haley VA Hospital between 9/2009 and 8/2013 were retrospectively studied and assigned a BSRTC category. Cytology categories included: nondiagnostic, benign, atypia of undetermined significance (AUS)/follicular lesion of undetermined significance (FLUS), suspicious for follicular neoplasm, suspicious for malignancy and malignant. Frequency of each category was determined. The histopathological reports of the nodules surgically excised were reviewed and malignancy rate for each category was established. Out of 766 thyroid nodules included, 12.8% was surgically excised and each histopathology report was reviewed. The mean age in the study was 58.6 years and 80% of patients were male. The FNA cytology results showed: 6.9% nondiagnostic, 62.7% benign, 22.4% AUS/FLUS, 4% suspicious for follicular neoplasm, 1.6% suspicious for malignancy, 2% malignant. Malignancy was confirmed in 9.1% of benign nodules, 15.6% of AUS/FLUS, 29.4% of suspicious for follicular neoplasm, 71% of suspicious for malignancy and 100% of malignant nodules. The overall sensitivity of BSRTC was 90%, specificity 83.33% with PPV of 58.06% and NPV of 97.01%. In a male predominant patient population like our institution and other VA centers, the risk of malignancy for the different BSRTC categories is similar to that reported in other studies. The higher frequency than predicted by BSRTC of the AUS/FLUS category, may be due to its subjectivity; however its malignancy risk is comparable to the predicted by BSRTC. This study has helped our institution to improve the diagnostic accuracy of the BSRTC and to implement the molecular markers utilization in a very cost-effective manner.
Thyroid Nodules & Goiter Thursday Poster Clinical
In 2015, American Thyroid Association (ATA) published guidelines, in which the malignant risk stratification of nodules was developed according to the ultrasound characteristics of thyroid nodules. Shear-wave elastography (SWE) is a new ultrasonic diagnostic technique that can directly and quantitatively measures the hardness of tissue. It can be used as an ultrasound indication to evaluate the thyroid nodules. This study is intended to explore whether combined application of SWE and ATA guideline can improve the diagnostic value of thyroid nodules. A prospective enrollment of 270 patients with thyroid nodules who underwent ultrasound examination and thyroidectomy in our hospital from January 20 to April 2018 was performed. All nodules were evaluated according to ATA risk stratification. SWE was performed to measure the maximum Young's modulus (Emax) of thyroid nodules. According to the largest diameter of thyroid nodules, they were divided into >1 cm group and ≤1 cm group.
Of the 270 thyroid nodules, 183 were malignant nodules and 87 were benign nodules. The sensitivity, specificity and accuracy of ATA guideline were 85.8%, 70.1%, and 80.7%, respectively. The best cut-off value of Emax is 24.58 kPa. The sensitivity, specificity and accuracy of Emax were of 80.9%, 56.3% and 73.0%. For combined application of SWE and ATA guideline, the sensitivity, specificity and accuracy were 90.2%, 69.0%, and 83.3%. For the nodules larger than 1cm, the diagnostic value of ATA guideline with SWE is better than ATA risk stratification alone (AUC 0.84 vs. 0.80, P < 0.05) and SWE alone (AUC 0.84 vs 0.78, P < 0.01). We also combined application of SWE for low and intermediate for malignancy nodules. For the nodules with Emax >24.58kpa, the risk stratification is increased by one level. For the nodules with Emax ≤24.58kpa, the risk stratification is decreased by one level. After adjustments, percentages of malignancy in the nodules with very low, low, intermediate, and high suspicion for malignancy were 0, 27.3%, 37.8%, and 76.9%.
The Emax of SWE contributes to the differential diagnosis of thyroid nodules. SWE combined with ATA guidelines further improves the diagnostic value of thyroid nodules.
Thyroid Nodules & Goiter Thursday Poster Clinical
The Afirma Genomic Sequencing Classifier (GSC) was designed to improve specificity for identification of benign thyroid nodules among cytologically indeterminate thyroid nodules (ITN) as compared to its predecessor the Gene Expression Classifier (GEC). Here we report the performance of GSC at our institution. The retrospective study of ITN at The Ohio State University submitted for GSC or GEC from 2/2011 to 6/2018. The treating physician determined patient management. Statistical analysis was performed with Fisher's extract test. Two-sided P values of less than 0.05 were considered statistically significant.114 samples from cytologically ITN were collected for GSC: 87(76.3%) with Bethesda III and 27(23.7%) with Bethesda IV. 113 (99%) samples were adequate for GSC testing. GSC was benign in 83 nodules (73.5%), suspicious in 30 (26.5%). Twenty-two of 30 GSC suspicious cases underwent surgery: 4 classic papillary thyroid carcinoma (PTC), 2 PTC oncocytic variant, 3 follicular variant PTC, 2 follicular thyroid carcinoma, 1 noninvasive follicular thyroid neoplasm with papillary-like nuclear features and 10 benign nodules. One of 83 GSC benign cases underwent surgery with benign results. The positive predictive value (PPV) of GSC was 54.6% for operated GSC suspicious patients with sensitivity 100% and specificity of 89.2%. Overall, 44.7% of GEC tested nodules underwent surgery. Among 403 ITN nodules adequate for GEC testing between 2/2011 and 7/2017, the benign call rate, PPV, NPV, sensitivity, and specificity among GEC tested nodules were 48.4%, 33%, 95%, 98%, and 15%, respectively. Long-term follow up is needed to confirm the benign nature of all molecularly benign unoperated nodules. Our GSC experience shows statistically significant increases in benign call rate compared to GEC.
Friday, October 5, 2018
Disorders of Thyroid Function Friday Poster Basic
The Na+/I-symporter (NIS), encoded by the SLC5A5gene, is the plasma membrane glycoprotein that mediates the active transport of I- into the thyroid gland, the first step in the biosynthesis of the iodine-containing hormones (T3 and T4)1. NIS traverses the membrane 13 times, and couples the inward translocation of Na+ down its electrochemical gradient to the inward transport of I- against its electrochemical gradient with an electrogenic 2 Na+: 1 I-stoichiometry. Detailed molecular analysis of congenital iodide transport defect (ITD)-causing NIS mutants has provided valuable mechanistic information on NIS; in particular, residues have been identified that are critical for NIS substrate binding, specificity, stoichiometry, and plasma membrane targeting2.
ITD is an autosomal recessive disorder in which the thyroid cannot actively accumulate I-. When patients are not treated very early in life, ITD leads to hypothyroidism, goiter, and even mental retardation. Recently, a homozygous missense mutation was reported in exon 8 of the SLC5A5 gene; it results in a Tyr-to-Asp substitution at position 348 of NIS3. Tyr 348 is located in transmembrane segment 9, which has the highest number of β-OH group–containing amino acids, some of which participate in Na+binding/translocation. We are elucidating the molecular requirements of NIS at position 348 by determining the properties of NIS mutant proteins with different amino acids at that position using radioiodide uptake assays, kinetics, flow cytometry, and other approaches. Our results demonstrate that, surprisingly, the OH group of Tyr 348 is not essential, as Tyr348Phe NIS is indistinguishable from WT NIS. We are investigating whether cells expressing Tyr348Asp NIS do not transport I-because this mutant is not properly targeted to the plasma membrane or because it is intrinsically inactive. These results will be discussed in the context of our 3D NIS homology model and the molecular mechanism of NIS. As NIS is increasingly widely used in imaging and treatment, the more we learn about its biophysics and biochemistry, the better placed we will be to extend its clinical use. 1. Dai et al1996, Nature. 2. Ravera et al 2017. Annu Rev Physiol. 3. Watanabe et al2018, Thyroid
Disorders of Thyroid Function Friday Poster Clinical
Management of hyperthyroidism is a controversial topic. Whether to place a patient on radioactive iodine (RAI), surgery or low dose Methimazole (MMI) therapy may be difficult to decide because there is little evidence published regarding the efficacy and prognosis of long term use of anti-thyroid drugs (ATD's) treatment vs RAI or surgery in the hispanic population. We report 5 cases of hyperthyroidism due to Grave's Disease (GD), Toxic Multinodular Goiter (TMN), and Toxic Adenoma (TA) who were treated with ATD's for more than 2 years after completing initial MMI treatment; and a brief review of the literature supporting the use of prolonged ATD's in the treatment of hyperthyroidism over RAI. We retrospectively reviewed patients who received ATD's more than two years after completing initial ATD course in our clinics. Four cases denied RAI/surgical treatment and 1 case of GD who failed RAI treatment and denied a second course. Data gathered included TSH, Free T4, symptoms, treatment and complications. A retrospective review indicated that the mean duration of treatment at the time of data gathering was 74 months. All patients were female and used MMI. Non compliance was seen in 3 cases, one developing a rash after 60 months of treatment. Euthyroidism was reported in two patients diagnosed with TMN. A patient with GD and another with GD+TMN had laboratory values oscillating between euthyroidism and asymptomatic sub-clinical hyperthyroidism. These patients didn't develop osteoporosis or arrythmia. The patient with TA didn't achieve euthyroidism. Complication rate was low. One patient developed a minor side effect due to MMI. Compliance is one element affecting our results due to socioeconomic factors affecting this population. The sample of cases is very small, in part because current ATA guidelines favor RAI over continued ATD use. This data shows that achieving euthyroidism or asymptomatic subclinical hyperthyroidism is possible with prolonged treatment with ATD's. This serves to open an important discussion on wether MMI should be considered as primary treatment of hyperthyroidism and promotes research in the area, fundamental when trying to improve current treatment modalities.
Disorders of Thyroid Function Friday Poster Clinical
The burden of thyroid disease among lower income populations is not known. Because TSH deviations represent the earliest and most specific sign of thyroid disease, the incidence and prevalence of thyroid disease can be measured by TSH screening. Most low income populations, however, lack access to TSH assays. We have developed a smartphone point-of-care TSH immunochromatographic assay to provide affordable and available screening for primary hypothyroidism.
The quantitative immunochromatographic assay uses 40 microliters of plasma to measure TSH in the range 0.5 – 100 mIU/L in 20 minutes at room temperature. The assay generates a test line with an intensity that correlates with the TSH concentration. Using a smartphone attachment to control position and illumination, an image of the test result is acquired by the smartphone camera. A smartphone app processes this image to generate a quantitative TSH value and uploads each image for data archiving. Analytic precision is <20% for TSH concentrations between 5 – 30 mIU/L. Other glycoprotein hormones, hemoglobin, and lipemia do not interfere with assay performance.
We have tested the performance of this technology in a primary care clinic located in Bommanahalli, Bangalore, India. The clinic nurse performed 27 TSH measurements over 15 days using clinical laboratory performance standards. Using a cutoff of 4.0 mIU/L, 8 of 9 samples with TSH <4.0 and 15 of 16 samples with TSH >4.0 were correctly identified. These results demonstrate that a smartphone point-of-care TSH assay can reliably detect TSH elevations for rapid and inexpensive early detection of hypothyroidism, a common chronic disease.
Disorders of Thyroid Function Friday Poster Clinical
Definition of reference ranges for thyroid function tests, such as TSH, is a difficult task due to several biological and clinical factors, including age. Particularly for elderly population, several studies demonstrated a progressive increase in age-related TSH. Therefore, the aim of this study is to establish specific reference values for Brazilian population over 60 years old using Big Data strategy.
Data from 1 million TSH samples were retrospectively analyzed, and filtered using concentration within the reference values for free T4, anti-thyroid antibodies and the absence of medication use. Comparisons were made between TSH concentrations among two age groups, from 18 to 59 years old (under-60), and over 60 up to 107 years old (over-60). Basic statistical analyzes were performed using R software and EP Evaluator. Both R package ‘boot’ and EP Evaluator nonparametric (CLSI C28-A) were used to estimate the 95% confidence interval (IC) for the mean.
From the initial group of 1 million TSH samples, 23,968 were selected. Mean TSH was similar in both sex, but with noticeably difference between the two age-groups with lower reference value of 0.35 mUI/L (95% IC = 0.30, 0.40) and upper reference value of 9.60 mUI/L (95% IC = 8.60, 10.50) in over-60 group and 0.59 mUI/L (95% IC = 0.57, 0.61) and 6.10 mUI/L (95% IC = 6.00, 6.20) in under-60 group. Additionally, the upper limit of reference range increases within the older group with TSH of 7.5 mUI/L from 60 to 69, 9.58 mUI/L from 70 to 79 and 13.7 mUI/L above 80 years old.
The analysis of a large cohort of TSH tests in a Brazilian population demonstrated an increase in upper reference limit in patients over 60 years old. This new age-specific TSH reference value is important to avoid overdiagnosis of subclinical hypothyroidism in this population.
Iodine Uptake & Metabolism Friday Poster Clinical
Dyshormonogenic congenital hypothyroidism is caused by loss-of-function mutations in genes required for normal thyroid hormonogenesis. Particularly, mutations in the Na+/I− symporter (NIS)-coding SLC5A5 gene cause an uncommon autosomal recessive disorder known as I− transport defect (ITD), as a consequence of impaired I− accumulation in the thyroid follicular cell. Genomic DNA was isolated from hole blood and the entire exonic nucleotide sequence encoding the SLC5A5 gene was studied using Sanger sequencing. Genetic testing was approved by the institutional review board at Hospital de Niños Dr. Ricardo Gutiérrez. In silico computational and in vitro functional studies of newly identified NIS mutants were performed. Three unrelated female pediatric patients were diagnosed by neonatal screening with severe dyshormonogenic congenital hypothyroidism. ITD was suspected on the basis of non-detectable radioiodide accumulation in a normally located, non-goitrous thyroid gland, as well as in salivary glands.
SLC5A5 gene analysis revealed six non-synonymous compound heterozygous variants (p.Q136L/p.D369V, p.D331N/p.S547R, and p.G543K/p.L562M) in association with an ITD phenotype. Notably, none of them were reported in the Exome Aggregation Consortium database.
The pathologic significance of all NIS mutants was investigated in silico using prediction softwares (i.e. SIFT, Polyphen-2, and MutationTaster). Prediction programs indicated that all NIS mutants might be disease associated.
Functional studies in vitro demonstrated that the NIS mutants p.D369V, p.S547R, and P.G543K were associated with non-detectable I− accumulation when transiently transfected into HEK-293T cells, which do not express NIS endogenously. The NIS mutants p.Q136L, p.D331N, and L562M have not been tested yet. Moreover, flow cytometry, immunofluorescence and immunoblot analysis revealed that these mutant proteins are completely retained in the endoplasmic reticulum and, therefore do not reach the plasma membrane. Although the mechanism by which these mutants impair NIS transport to the plasma membrane remains unknown, here we provide a brief characterization of novel molecular events leading to defective I- accumulation in the thyroid follicular cell.
Thyroid Cancer Friday Poster Basic
BRAFV600E is the most common genetic alteration in thyroid cancer, however intrinsic feedback mechanism limited the clinical application of BRAFV600E specific inhibitors. Synthetic lethal is a kind of interaction between two genes that only perturb both of the genes simultaneously lead to lethality, it provide an alternative paradigm to target non-druggable mutations of tumor. As metabolic alterations act as a hallmark of cancer, approaches utilize metabolic properties specific in distinct oncogenic backgrounds can be considered to achieve synthetic lethality in cancer cells. Inspired by the conception of synthetic lethal which may provide alternative methods to target BRAFV600E, we screened out CYP2S1 as a potential synthetic lethal partner of BRAFV600E, whose role in thyroid cancer is largely unknown. We evaluated the effects of CYP2S1 knock down in both BRAFWT and BRAFV600E mutated thyroid cancer cell lines through a series of in vitro and in vivo experiments, and explore the internal linkage between CYP2S1 and BRAFV600E by using western blot, qRT-PCR and dual-luciferase reporter assay. Our data show that knock down of CYP2S1 specifically suppress proliferation and promote apoptosis of human thyroid cancer cell lines expressing BRAFV600E, and also, inhibition of CYP2S1 is selective against BRAFV600E in xenograft tumor models. Mechanically, BRAFV600E mutation activate the MAPK/ERK signals and upregulate the expression of CYP2S1 through the AHR pathway, on the contrary, activation of AHR is also dependent on CYP2S1. Our data identified CYP2S1 as a synthetic lethal partner of BRAFV600E in thyroid cancer. Also, these study reveal that BRAFV600E can regulate CYP2S1 through AHR, while the CYP2S1-AHR feedback loop can amplify the signal from BRAFV600E, thus promote tumor development of BRAFV600E thyroid cancer.
Thyroid Cancer Friday Poster Basic
RAF inhibitor vemurafenib is a promising anticancer agent for patients with BRAF-mutant metastatic melanoma. However, BRAF-mutant thyroid cancer is relatively less sensitive to vemurafenib, and the reason for this discrepancy remains unclear. VCAM-1 recently has been demonstrated to play a role in tumor invasion and metastasis and could be related with the response to chemotherapy. To date, the role of VCAM-1 during BRAF inhibition in thyroid cancer remains unknown. RAF inhibitor vemurafenib is a promising anticancer agent for patients with BRAF-mutant metastatic melanoma. However, BRAF-mutant thyroid cancer is relatively less sensitive to vemurafenib, and the reason for this discrepancy remains unclear. VCAM-1 recently has been demonstrated to play a role in tumor invasion and metastasis and could be related with the response to chemotherapy. To date, the role of VCAM-1 during BRAF inhibition in thyroid cancer remains unknown. VCAM-1 was induced significantly by vemurafenib in thyroid cancer cell BCPAP, in both time-dependent and dose-dependent manner. Reverting the up-regulated VCAM-1 by RNA interfering facilitated the anti-tumor effects to vemurafenib. By contrast, overexpression of VCAM-1 in thyroid cancer cell FRO reduced the sensitivity to vemurafenib. Signaling pathway analysis showed combined inhibition of Akt signaling pathway by MK2206 reversed the expression of up-regulated VCAM1 during BRAF inhibition and synergistically inhibited thyroid cancer cell growth. Moreover, stable expression of VCAM-1 promoted tumor invasiveness and metastasis in thyroid cancer cell and correlated with malignant clinicopathologic features. This study, to our best knowledge, is the first to demonstrate that the up-regulated VCAM-1 promotes thyroid cancer resistant to BRAF inhibitor. Combination of AKT inhibitor or inhibition of VCAM-1 expression may be an alternative strategy to sensitize BRAF-mutant thyroid cancer to vemurafenib.
Thyroid Cancer Friday Poster Case Report
Distant metastases are not very common in differentiated thyroid cancer (DTC), but are often detected in the radioiodine refractory DTC (RAIR-DTC) patients. The most common sites of distant metastases are lung, bone or brain. Transversus abdominis muscle metastasis is extremely rare. Herein, we report a case of unusual transversus abdominis muscle metastasis from RAIR-DTC incidentally detected by 18F-FDG PET/CT. This is a 48-year-old man with enlargement neck mass was pathologically diagnosed as solid variant of papillary thyroid cancer (PTC), staged as pT4aN1b (AJCC 8th edition) after total thyroidectomy and lymph node dissection in 2016. As his preoperative chest CT showed highly suspicious multiple pulmonary metastases, subsequent twice radioiodine (RAI) therapy was conducted after a low-iodine diet and thyroid hormone withdrawal, with RAI doses 5.55GBq and 6.475GBq with an interval of 6 months. Then he was diagnosed as RAIR-DTC as his pulmonary metastases presented as non-iodine-avidity on posttreatment 131I whole body scan. A rapidly increasing thyroglobulin (Tg) (from 593.9 ng/ml to 917.8 ng/ml) was observed in 3 months after the 2nd RAI therapy, which was inconsistent with his relatively stable pulmonary metastases on serial chest CT. Therefore, a 18F-FDG PET/CT was performed for comprehensive tumor burden assessment. The 18F-FDG PET/CT showed multiple hypermetabolic foci in lungs, bones and transversus abdominis muscle, which was confirmed as thyroid cancer metastatic lesion by CT-guided biopsy. This patient was previously diagnosed as RAIR-DTC with lung metastases, previously unknown bone metastases and rare muscle metastases were detected in 18F-FDG PET/CT.18F-FDG PET/CT can accurately assess the tumor burden of RAIR-DTC, and may alter the therapy management of some patients.
Thyroid Cancer Friday Poster Clinical
We report interim results of a multicenter registry study of patients with thyroid nodules indeterminate by cytology that underwent combined mutation (ThyGenX) and microRNA (ThyraMIR) testing in clinical practice. We examined the likelihood at which patients avoided surgery and survived without developing malignancy given combined test results. All patients underwent past clinical ThyGenX and ThyraMIR (T/T) testing and had either positive or negative combined test results as previously described [1]. ThyGenX testing included common oncogenic mutations and fusion transcripts. ThyraMIR testing included expression classification of 10 microRNAs. Results from 9 institutions were examined. Baseline clinical information at the time of T/T testing and follow-up records were reviewed. Malignant events were considered only when pathology confirmed carcinoma was found. Kaplan-Meier analysis was used to determine the cumulative probability of survival without having a surgical procedure or malignant diagnosis over the course of patient follow-up. The interim cohort consisted of 180 patients with indeterminate nodules at baseline of which 55% had clinical follow-up for up to 2 years post testing. Overall, 86% met criteria for a benign diagnosis and 14% for malignant. 69% had negative T/T results, and those patients had a 92% likelihood of benign disease for up to 2 years follow-up. They were 66% less likely to undergo surgery than patients with T/T positive results. Patients with T/T positive results had a 57% probability of malignancy at follow-up and a 97% likelihood of undergoing surgery. Results of combined mutation and microRNA testing influence surgical decisions in clinical practice. Decisions for surgery were appropriately aligned with risk of developing malignancy at follow-up, given a combination test that effectively both rules in (ThyGenX) and rules out (ThyraMIR) higher risk of malignancy.
Thyroid Cancer Friday Poster Clinical
Hyperthyroidism is linked to prognosis of differentiated thyroid carcinoma (DTC). It is still controversial whether hyperthyroid DTC can be more aggressive than euthyroid DTC. We conducted systematic review and meta-analysis to examine the association of hyperthyroidism and overall mortality in patients with DTC. We comprehensively searched the databases of MEDLINE and EMBASE from inception to July 2018. Included studies were published studies that compared the risk of mortality and prognosis between DTC patients with hyperthyroidism and those with euthyroidism. Data from each study were combined using the random-effects model. Nine studies from April 1990 to May 2018 were included (401 hyperthyroid DTC patients and 1644 euthyroid DTC patients). The DTC patients with hyperthyroidism had a significant higher risk of associated multifocality (risk ratio = 1.35, 95% confidence interval: 1.04-1.77, I2 = 0.0%, p = 0.026) as well as overall mortality (risk ratio = 3.63, 95% confidence interval: 1.51-8.75, I2 = 14.5, p = 0.004). DTC patients with hyperthyroidism have higher risk of mortality than those with euthyroidism. Our study suggests that DTC patients with hyperthyroidism should be carefully monitored and evaluated with thyroglobulin panel and imaging studies such as ultrasound and/or scintigraphy to prevent underestimation of cancer severity.
Thyroid Cancer Friday Poster Clinical
Molecular testing for indeterminate thyroid nodules has decreased the need for diagnostic surgery. Recent advances in molecular testing techniques have not been independently validated. The objective of this study was to compare the diagnostic performance of Afirma Genomic Sequencing Classifier (GSC) and ThyroSeq v3. Patients who underwent thyroid nodule biopsy at UCLA (8/2017 – 6/2018) were block randomized by month to GSC or ThyroSeq v3. A molecular test sample was collected during the biopsy and reflexively sent if the FNA was indeterminate (Bethesda 3 or 4). Treatment recommendations were made using best practices that incorporated molecular test results. Surgically resected nodules underwent histopathologic evaluation, while the remainder was followed with annual ultrasounds. Specificity was compared to those of the prior molecular test versions (Afirma Gene Expression Classifier and ThyroSeq v2, respectively) from our previous randomized study. Of 1,167 thyroid nodules, 73.7% were benign, 8.9% were suspicious for malignancy / malignant, and 12.1% were indeterminate. Of the indeterminate group, 131 nodules (92.3%) were included in the study (median patient age 55 years, 78% female, median nodule size 2.1 cm). Of nodules tested with GSC (N = 71), 48.4% were suspicious, 46.8% were benign, and 4.8% were insufficient for analysis. Of nodules tested with ThyroSeq v3 (N = 58), 44.6% had a positive mutation, 53.6% had no mutations, and 1.8% were insufficient. The positive predictive values were 63.2%% for GSC and 61.5% for ThyroSeq v3, with a 26.7% prevalence of malignancy. Compared to the previous test versions, the specificity of Afirma increased from 66.0% to 77.4% and the specificity of ThyroSeq decreased from 90.6% to 79.2%. In this sample, GSC and ThyroSeq v3 had a similar distribution of benign versus suspicious results and were comparable in diagnostic performance. Long-term ultrasound surveillance is crucial to compare the false-negative rates between these molecular tests.
Thyroid Cancer Friday Poster Clinical
Pediatric thyroid cancer (TC) is rare. However, lung metastases in this age group are more common than in adult TC. We present an analysis of a series of lung metastasis in pediatric TC focusing on their radiological pattern, underlying mutations, response to therapy and long-term outcomeOut of 110 patients with pediatric TC managed during the period 1998-2017, 21 patients (16 females, 4 males, median age 14.5 years, range 10-18) had lung metastases. One patient was lost to follow up. Data on the other 20 patients were analyzed. The tumors include differentiated thyroid cancer in 19 patients and a single case of poorly differentiated thyroid cancer. Lung metastasis presented with 3 distinct radiological patterns: lung uptake on diagnostic radioiodine whole body scan (DxWBS) only in 3 patients (15%), on DxWBS and CT scan as micro metastases (≤ 1 cm in size) in 16 patients (80%) and on DxWBS and CT scan as macrometastases (>1 cm) in 1 patient (5%). I-131 therapies were administered to all patients (median number 3, range 1-8) with a median cumulative administered activity of 317.5 mCi (range 109-682). None of the patients achieved a complete response but there was a substantial biochemical response. The median stimulated Tg at the time of first I-131 was 889.5 ng/dl (4.1-8825) and at the last visit was 10.5 ng/dl (0-1226). Over a median follow up of 8.2 years (range 0.75-16.3), 1 patient (5%) with poorly differentiated TC died, 1 patient (5%) had a biochemically incomplete response, 2 patients (10%) had an indeterminate response, 1 patient (5%) had progressive structural disease and 14 patients (70%) had stable structural disease. Mutational testing of 10/20 tumors that were available revealed only two PIK3CA mutations in a single tumor.
Lung metastases are common in pediatric TC and present most frequently with bilateral radioiodine-avid micrometastases. Known single point mutations in adult TC are rare in pediatric TC. Biochemical response to I-131 is substantial but resolution of structural abnormalities is rare and most patients continue to have stable structural disease in the form of lung micrometastases. Death from lung metastasis is rare.
Thyroid Cancer Friday Poster Clinical
On the basis of previous feasibility studies (1, 2) we evaluated tolerability, safety, clinical outcomes and costs of ultrasound (US)-guided percutaneous laser ablation (LA) for local control of cervical recurrences of thyroid cancer. From December 2013 to December 2017, 37 cervical recurrences of 31 patients (12M and 19F, mean age 60 yrs) were treated with LA. After total-thyroidectomy (23 papillary, 4 follicular and 4 medullary cancers) patients had undergone one to three cervical lymphadenectomies and presented further radioiodine-refractory recurrences. Ten patients (32.2%) presented distant metastasis. LA was performed in an outpatient setting with 1 or 2 optical fibers and a Nd:YAG laser source (Echolaser, Elesta, Italy), with energy delivery of 500-6000 Joules (2) on the basis of lesion volume. Treatment was followed by a single steroid and analgesic administration. Cervical US was performed at 1, 6 and 12 months. Pain and tolerability were assessed with validated analogic questionnaires and side-effects and complications were registered. LA was defined as well tolerated (25 of 31 patients, 80.6%) and analgesics by mouth were required for a mean 1.5 days (range 1–3 days). No complications were registered and no patient required hospitalization. After 24 hours, color-Doppler and contrast-enhanced US demonstrated disappearance of vascular signals within treated area. Mean volume of the lesions decreased from 3.0 ± 4.8 at baseline to 1.1 ± 2.2 (-39%) at 1 month, to 0.95 ± 1.7 (-70%) at 6 months and to 0.06 ± 0.8 ml (-80%) at 12 months. Italian Health Service reimbursement is 901 Euro for LA vs 5308 Euro for surgical lymphadenectomy. LA is a well-tolerated and safe procedure for the management of cervical recurrences. The procedure results in effective control of local disease and is performed on outpatients. The direct costs of surgery are six times greater than the total cost of LA.
Thyroid Cancer Friday Poster Clinical
Calcitonin and CEA doubling times have been used to estimate the prognosis in patients with medullary thyroid cancer (MTC). The relationship between tumor growth rates and tumor marker changes has not been described in patients with metastatic MTC. The objective of this study was to characterize tumor growth rates measured by tumor volume doubling time (TVDT) and evaluate its correlation with calcitonin and CEA doubling times in patients with metastatic MTC. Patients with MTC followed at Moffitt Cancer Center from 1996 to 2018 who had serial consecutive tumor markers measurements and imaging studies of liver, lungs, or mediastinum metastasis were included. We calculated calcitonin and CEA doubling times as well as average TVDT for two metastatic lesions, before and during systemic therapy, if patients were treated with it. Thirty patients (53.3% female, mean age of diagnosis 57.5 years) were evaluated with median follow up of 5 years (0.7-50). 15 (50%) patients had distant metastatic disease at presentation and 46.7% were treated with systemic therapy (11 of 14 patients were on multikinase inhibitors). Tumor growth was constant over time (the mean correlation coefficient 0.87 and coefficient of determination 0.75) and followed classical exponential tumor growth pattern. The correlation between calcitonin and CEA doubling times and TVDT was stronger on systemic therapy compared to prior to starting the systemic therapy (Pearson correlation −0.55 and −0.67 compared to −0.24 and −0.33, respectively). The changes in the CEA doubling time reflected tumor progression rates better than calcitonin, particularly while on systemic therapy. Calcitonin and, perhaps more importantly, CEA doubling times can be used as markers of tumor progression. Tumor markers doubling time can be utilized in determining the timing for systemic therapy initiation and response to it and further study is warranted.
Thyroid Cancer Friday Poster Translational
Common cancer classification and discovery schemes that focus on identifying discrete genetic alterations or that rely explicitly on histopathology are poorly equipped to characterize tumor behavior. We describe the Oncogenic Positioning System (Onco-GPS), a novel, data-driven computational framework designed to decompose tumor sample transcriptional signatures into distinct “transcriptional components”, each characterized by varying concordance with series of functional transcriptional pathways. These components are used to deconstruct and define “cellular” or “oncogenic states”, each of which represents a computationally-derived cluster of functionally similar tumor samples. Applications of the methodology in papillary thyroid cancer (PTC) are herein presented. Primary data (RNAseq, miRNA, mutational profile, DNA methylation, proteins) pertaining to 505 PTC tumor samples was derived from the The Cancer Genome Atlas (TCGA) database. Single sample gene set enrichment analysis (ssGSEA) was performed to obtain pathway expression scores. The OncoGPS methodology was then applied to define five transcriptional components and six oncogenic states. Tumor samples harboring BRAF and RET fusion gene mutations aggregated in the same three states, while RAS-mutant tumors stratified primarily to two different states. Tumors with other driver mutations, including CHEK2, E1FAX, and PPM1D, did not follow a state-driven distribution. The transcriptional component forming the epicenter of two of the BRAF mutant states was characterized by significant enrichment (information coefficient [IC] = 0.823) in ZEB1 target genes, implying a mesenchymal phenotype. One state was composed predominantly of follicular-variant PTC (FV-PTC) tumor samples, the molecular hallmarks of which included high PI3K/AKT (IC = 0.707) and YAP (IC = 0.678) pathway expression; clinical hallmarks included increased differentiation and lower incidence of nodal spread. A data-driven, analytic approach to tumor classification may facilitate identification of novel diagnostic biomarkers, more granular prognostication, and, ultimately, the ability to infer molecular treatment targets using an explicitly computational approach to inform future translational studies.
Thyroid Cancer Friday Poster Translational
Thyroid cancer patients with radioiodine refractory (RAIR) disease, due to either insufficient RAI delivery or RAI resistance, have increased mortality with few available treatments. To date, the genetic landscape underlying the phenotypic heterogeneity observed in RAIR disease has not been investigated. Germline single nucleotide polymorphism (SNP) association analyses were conducted using 1) candidate genes involved in DNA-damage repair (N = 86) and iodine metabolism (N = 15) and 2) genome wide association analysis in our cohort of RAI treated African American (AA) (RAIR N = 9; Non-RAIR N = 46) and Caucasian (CAU) (RAIR N = 244; Non-RAIR N = 901) thyroid cancer patients. We noted a higher incidence of RAIR disease (N = 7) occurred in AA patients with >80% African ancestry (N = 34). Thus, we focused on identifying SNPs uniquely associated with RAIR AA patients with high African ancestry.1) Germline SNPs comprising a haplotype in an iodine metabolism gene were associated uniquely with 4/7 RAIR AA patients, all of whom have an incomplete biochemical response to RAI therapy, and 2) germline SNPs on chromosome 8, that encompass a gene involved in double-stranded DNA break repair were uniquely associated with 4 RAIR AA patients diagnosed at a young age (13, 17, 17, and 26 years old) with distant metastatic disease at initial diagnosis. Three of these patients also have a large haplotype on chromosome 17 in a DNA-damage repair gene. The aforementioned germline SNPs were not present in any other patients of the cohort. It has been reported that thyroid cancer incidence is lower in AA patients, yet their diseases tend to be more aggressive. Our study on candidate RAIR predisposing germline SNPs in AA patients will help identify AA patients at risk for RAIR disease for early intervention. Analysis of whole exome sequencing from paired blood and tumor DNA samples from 10 patients (RAIR N = 3, Non-RAIR N = 7) is ongoing to identify tumor mutation landscapes unique to RAIR AA patients. Further investigation of the effects of these germline SNPs will provide insight into the mechanisms underlying RAIR disease across all ethnicities.
Thyroid Hormone Metabolism & Regulation Friday Poster Basic
Methimazole (MMI) is commonly used to treat hyperthyroidism by blocking thyroxine biosynthesis in thyrocytes; however, MMI was also shown to downregulate expression of the major histocompatibility (MHC) genes, I and II, which suggested it might also possess anti-inflammatory and immunoregulatory activity. Moreover, decreased thyroid hormone production is associated with a variety of immunological manifestations, such as reduced activation of CD4+ cells, increased CD8+ cell activity. Experiment studies have shown that MMI induced hypothyroidism reduced the phagocytosis ability of alveolar macrophages. In tumor transplant rodent models, thyroxine appear to stimulate tumor growth and metastasis, whereas hypothyroidism induced by MMI has opposite effects. Metastasis is the main cause of death in cancer patients. To improve the outcomes of patients undergoing a surgery, new adjuvant therapies that can effectively inhibit metastases have to be developed. We hypothesized that early treatment with MMI between the time of diagnosis and definitive surgery, the so-called “window-of-opportunity,” can inhibit pulmonary metastasis. To investigate our hypothesis, a breast cancer resection model that mimics clinical situations was established. the mice were provided with with 0.1% MMI in water (w/v) ad librium, starting after the initial detection of the primary tumor. Two weeks later, the primary tumors were excised and analyzed for epithelial cell adhesion molecule (EpCAM) expression, CD4+ and CD8+ T cell infiltration, and the MMI treatment was discontinued. After two weeks, the animals were sacrificed and their lungs analyzed histologically for number of metastases and metastatic burden (metastases' area/lung section area). MMI treatment reduced significantly pulmonary metastasis number and metastatic burden, and increased CD8 + T cells infiltration in the primary tumor, accompanied by reduced expression of EpCAM, relative to control vehicle. The data we report here show that MMI suppressed primar and metastatic tumor growth, indicating presurgical administration of MMI as a pharmacologic approach to block breast cancer progression/recurrence after surgery and increase breast cancer cure rates.
Thyroid Imaging Friday Poster Clinical
Ultrasound (US) is increasingly indispensable for evaluation of thyroid nodules. Many US risk stratification systems have been proposed to help determine which nodules warrant biopsy. Although these systems are validated, few studies have directly compared systems. We compared the two most popular systems currently used, the 2015 American Thyroid Association (ATA) guidelines and the American College of Radiology Thyroid Imaging and Reporting Data System (ACR TIRADS). We retrospectively identified 250 thyroid nodules that were surgically removed. Their US images were independently reviewed by four raters using ATA and three raters using ACR TIRADS. Raters included endocrinologists, endocrine surgeons and radiologists with expertise in US. Chi-square was used to compare observed vs expected malignancy rates and Fleiss' kappa coefficient for interobserver agreement within each system. To compare performance, we generated the receiver operator curve of each logistic regression model, calculated the area under the curve and compared using linear predictors of the curve.70 (28%) nodules were malignant. Mean nodule size was 26mm (10-72mm).
Observed and expected malignancy rates for ATA risk strata were not different except for nodules rated “intermediate suspicion” where 44% vs 10-20% were malignant (p = 0.003). Greater discordance between observed and expected malignancy rates was noted with ACR TIRADS, specifically category 3 (19% vs ≤5%, p = 0.004), 4 (42% vs 5.1-20%, p = 0.008) and 5 (62% vs >20%, p = 0.001).
Based on mean rating and nodule size, ATA would have recommended biopsy in 218 nodules and ACR TIRADS in 134 nodules. Based on surgical pathology, the sensitivity, specificity, negative predictive and positive predictive values for ATA were 91%, 14%, 81% and 29%, respectively, and for ACR TIRADS 73%, 54%, 84% and 38%, respectively. AUCs for ATA was 0.7681 (95CI: 0.70748, 0.82871) and for ACR TI-RADS was 0.7239 (95CI: 0.66007, 0.78779), p = 0.034.
There was “fair agreement” amongst raters for ATA (κ = 0.324) and ACR TIRADS (κ = 0.342). ATA had greater concordance between observed and expected malignancy risk per strata and better diagnostic performance than ACR TIRADS. Both systems exhibit fair interobserver agreement.
Thyroid Nodules & Goiter Friday Poster Basic
The prevalence of TSHR and Gsa mutations in hot thyroid adenoma (HTA) has been reported to vary from 8 to 82%. A comprehensive study of our group using denaturing gradient gel electrophoresis (DGGE), revealed a frequency of 57% TSHR mutations and 3% Gsa mutations in 75 consecutive HTA. However, DGGE has a limited sensitivity and is subjective limiting its diagnostic performance. We now report an increased mutation frequency in HTA due to an increased sensitivity of more recent mutation detection methodologies. Targeted next generation sequencing (NGS) was used to analyze high resolution melting (HRM) PCR mutation negative samples.
Available samples from three previous studies that were found to be mutation negative by DGGE were selected and re-evaluated using the more sensitive HRM PCR. Remaining mutation negative samples were re-analyzed using tNGS with a depth of coverage between 3000X and 10000X. Our targeted NGS panel consisted of the entire TSHR and hot spot regions in Gsa and EZH1. Of the 207 HTA available samples with previous analysis by DGGE and HRM, DGGE had previously found 111 mutation positive samples (54%). HRM found mutations in an additional 46 samples (22%) resulting in a total of 76% mutation positive. In the remaining 50 samples that were mutation negative by DGGE and HRM, targeted NGS detected a total of 16 (32%) to have Gsa or TSHR mutations. There were 4 samples with Gsa mutations and 12 with TSHR mutations and one additional sample with a mutation in both genes. In summary 84% of HTA have these mutations, with 80% of samples containing TSHR mutations and 4% containing Gsa mutations.
The higher sensitivity of targeted NGS has allowed us to better determine the frequency of TSHR and Gsa mutation in a large set of HTA. It is unlikely that the remaining 16% of hot nodules harbour TSHR or Gsa mutations based on our depth of sequencing and our findings of 6 mutations with mutated allele frequencies of 3-5%. Interestingly in our previous whole exome sequencing analysis of 15 TSHR and Gsa mutation negative hot nodules, we found only EZH1 mutations as additional reoccurring mutations.
Thyroid Nodules & Goiter Friday Poster Clinical
Cytology from thyroid nodule biopsy often shows atypia of undetermined significance (AUS) leading to surgery for ultimately benign histology. Molecular testing, such as ThyGenX, can augment clinical decision making in thyroid nodule management. This project examined ThyGenX testing in the San Antonio Military Health System (SAMHS). This was a non-industry cost analysis and review of patients in the SAMHS who had thyroid nodule cytology with ThyGenX testing over an 18 month period of time. Over 18 months, 24 patients had ThyGenX testing because cytology showed AUS on 2 or more biopsies. Molecular testing identified mutations in 5 patients. 3 patients with a mutation underwent total thyroidectomy. Of these, 2 had papillary thyroid carcinoma and 1 had benign histology. Molecular testing showed no mutations in 19 patients; of these, 2 underwent hemithyroidectomy and histology was benign for both. ThyGenX testing costs approximately $2600 per sample in the SAMHS. Thyroidectomy with hospitalization costs about $12,800. The costs of clinical follow up with surgery, primary care, TSH testing, and long term levothyroxine therapy is approximately $15,000. ThyGenX testing cost approximately $62,400 for these 24 patients who would have otherwise gone for surgery, which would have cost SAMHS about $528,200. Thus, molecular testing spared 19 patients from surgery, saving approximately $466,000. Molecular testing for patients with indeterminate thyroid nodule cytology is a cost-effective tool in the SAMHS. No patients with negative molecular testing results had evidence of cancer on histology. This may help patients avoid unnecessary surgery and subsequent hypothyroidism. The cost of molecular testing is significant but far less than the cost of thyroidectomy with its associated care. Molecular testing to reduce unnecessary surgery represents a benefit to patients and a cost-savings to the SAMHS.
Thyroid Nodules & Goiter Friday Poster Clinical
For thyroid nodules with indeterminate FNA cytology (Bethesda class III or IV), the Afirma Gene Expression Classifier (GEC) classifies aspirates as benign or suspicious with high negative predictive value and reduces the need for diagnostic thyroid surgery. However, many benign lesions were classified as suspicious, particularly when cytology was characterized by Hurthle cells. The recently developed Afirma Genomic Sequencing Classifier (GSC) showed similar sensitivity with improved specificity, suggesting more nodules would have a benign result. A retrospective analysis of all thyroid nodules ≥1cm with Bethesda III or IV cytology tested with GEC or GSC from 2011-2018 at our institution. Demographic, sonographic and cytologic data were collected. The proportion of results that returned benign (the benign call rate [BCR]) for GEC versus GSC tested nodules was compared and further stratification of BCR was evaluated by Bethesda classifications. We evaluated 583 nodules in 546 patients tested with either GEC (n = 486) or GSC (n = 97). The GEC BCR was 233/486 (47.9%) compared to 63/97 (64.9%) for the GSC BCR (p = 0.003). In Bethesda III nodules characterized by Hurthle cells, the GSC BCR was 100% (5/5) versus 36.8% (14/38) for GEC BCR (p = 0.01), but the BCRs were similar for nodules with cytologic or architectural atypia. In Bethesda IV nodules, the BCR for follicular neoplasm was 63.1% (70/111) for GEC and 68.4% (13/19) for GSC (p = 0.68), but for cytology suspicious for Hurthle cell neoplasm, the GSC BCR was 68.2% (15/22) compared to the GEC BCR of only 16.4% (10/61) (p < 0.0001). Demographic parameters were similar between groups. GSC tested nodules tended to be larger compared to GEC group (2.1 vs. 1.9 cm, p = 0.06), and were less likely to be >50% cystic (3/97[3.1%] vs 56/486 [11.5%], p = 0.009), though the distribution of ATA sonographic risk patterns was similar between groups. The GSC identified a higher percentage of benign results compared to the GEC for indeterminate thyroid nodules, predominantly due to improved BCR among nodules with Hurthle cell cytology. The clinical result is likely further reduction in surgical management.
Thyroid Nodules & Goiter Friday Poster Clinical
Intra-operative neuromonitoring (IONM) of the vagus and recurrent laryngeal nerves (RLN) can be performed in intermittently or continuously. The only commercially available continuous neuromonitoring technique requires placement of a vagus nerve electrode. In 2016, we discovered a new technique of continuous vagal monitoring using the laryngeal adductor reflex (LAR-CIONM). Herein we present data from 200 nerves-at-risk successfully monitored using this technique. The LAR was elicited by electrical stimulation of laryngeal mucosa on the side contralateral to the operative field using endotracheal tube electrodes. Ipsilateral electrodes recorded EMG responses from vocal fold adduction. All patients completed pre- and post-operative flexible transnasal laryngoscopy and vocal handicap index-10 questionnaires.160 (200 nerves-at-risk) undergoing neck endocrine surgeries were included (thyroidectomy n = 179, parathyroidectomy n = 21). Five patients had transient post–operative vocal fold paralysis, 3 of which were unanticipated (1.5%). All palsies occurred in the first 12 months of using the technique when the surgeon preferentially relied upon intermittent nerve monitoring. Since the surgeon has relied predominantly on LAR-CIONM, there have been no further unanticipated nerve injuries. LAR amplitude decrement >60% of baseline which persisted despite release of retracted tissues reliably prediced post-operative vocal fold paralysis. LAR-CIONM was highly sensitive to RLN stretch or compression. There were no complications attributable to LAR-CIONM monitoring for any patient peri- or post-operatively. LAR-CIONM is a reliable and novel method of continuous vagal monitoring. It requires no equipment other than an EMG endotracheal tube and specifically stimulates nerve fibers uninvolved in autonomic functions. It can monitor the entire vagal reflex arc with widespread applicability to any surgery placing the vagus nerve at risk, including posterior fossa approaches. It is starting to be used outside of our own institution and once endotracheal tube electrode design is optimized for this technique, it has the potential to revolutionize how we perform intraoperative continuous vagal nerve monitoring.
Saturday, October 6, 2018
Autoimmunity Saturday Poster Clinical
The impact of Hashimoto's thyroiditis (HT) upon the risk of thyroid cancer and its accurate detection, remains unclear. Prior studies are limited by retrospective design, selection bias, or their narrow definitions of HT. Importantly, the presence of a chronic lymphocytic infiltration imparts a logical mechanism potentially altering malignancy risk, while also influencing the accuracy of diagnostic evaluation. We performed a prospective, cohort analysis studying 9,985 consecutive patients with 21,740 thyroid nodules who underwent nodule evaluation between 1995-2017. To avoid selection bias while simultaneously applying the most translatable, real-world protocol, we utilized a holistic definition of HT which included a) positive thyroid peroxidase antibody (TPOAb) and/or, b) findings of diffuse heterogeneity on ultrasound, and/or c) the finding of diffuse lymphocytic thyroiditis on histopathology. All patients were evaluated per clinical guidelines applicable to the time of care. We then determined the impact of HT on the distribution of Bethesda cytology, and ultimately upon malignancy risk.2,682 patients (27%) were diagnosed with clinical, sonographic, or histologic evidence of HT. In total, 3,932 HT nodules, and 10,359 non-HT nodules, were biopsied, Nodules not biopsied were cystic, small, and likely benign. The prevalence of indeterminate and malignant cytology was higher in the HT vs. non-HT group (Indeterminate 20.6 vs. 17.1%, p < 0.001; Malignant: 7.6% vs. 4.8%, p < 0.001). Ultimately, the risk of any nodule proving malignant was significantly elevated in the setting of HT (23.0% vs. 15.8%; p < 0.001). This increased prevalence was maintained when patients with solitary or multiple nodules were analyzed separately, suggesting a field effect of HT itself (24.1 vs. 16.1% solitary; 21.5 vs. 15.2% multinodular). Hashimoto's thyroiditis increases the risk of thyroid malignancy in any patient presenting for nodule evaluation. Diffuse sonographic heterogeneity and/or TPO Ab positivity should be used for risk assessment at time of evaluation.
Disorders of Thyroid Function Saturday Poster Clinical
Thyroid dysfunction is the most common endocrine immune related adverse event (irAE) due to immune checkpoint inhibitor (ICPI) therapy. Incidence and course of thyroid irAEs are well characterized, but predicting recovery remains difficult. Glucocorticoid (GC) effect on thyroid irAEs is poorly defined; recovery has occurred with cases of thyroiditis, but rarely in other endocrine irAEs. Prior reports show improved overall survival (OS) in some patients that experienced some irAEs. Our aim was to describe thyroid dysfunction, factors associated with thyroid recovery, and survival in melanoma patients treated with ICPIs. A retrospective study in a tertiary center from 2010-2017. We included patients with melanoma and thyroid dysfunction that occurred after ICPI therapy, excluding any with hypophysitis, neck radiation, amiodarone, <2 abnormal thyroid function tests (TFTs), or prior thyroid dysfunction. Cases were divided by recovery ((R) return to baseline TFTs without medication in 1 year) and no recovery (NR). We collected a timeline of TFTs, GC exposure, and thyroid medication use. We studied OS in comparison to a matched group without thyroid dysfunction. Out of 186 melanoma patients that received ICPIs, 17 had thyroid irAEs. Median time to abnormal TSH after ICPI was 44 days and was suppressed in 14 of 17. Seven of 17 had thyroid recovery. In the NR group, Free T4 was more often above 2 ng/dL (5/10 in NR, 0/7 in R: p = 0.04). In the R group, irAE grade was significantly lower with 7/7 grade 1 (p = 0.004). Exposure to GC was associated with recovery (3/10 in NR, 6/7 in R: p = 0.049). There appeared to be no significant differences in OS between the thyroid dysfunction group and controls, or between those that received GC or not. Certain aspects of thyroid irAEs may relate to thyroid recovery. Grade 1 thyroid irAEs were more likely to recover to baseline TFTs, as were patients exposed to GC during irAEs. Free T4 levels above 2 ng/dL were associated with persistent thyroid dysfunction. Thyroid irAEs did not appear to be associated with change in OS, nor did exposure to GC. Monitoring of TFTs remains important during ICPI therapy, and further studies are needed to understand the effect of GC on thyroid irAEs.
Disorders of Thyroid Function Saturday Poster Clinical
In 20 hypothyroid patients (age 27-78 years; 11/20 = men) who were instructed to take simultaneously tablet L-T4 and calcium carbonate (CC) for 3 months, TSH increased by 80% (1.60 ± 0.22 to 2.88 ± 0.41 mU/L [mean±SE]) and it was above 4.0 mU/L in 4/20, indicating L-T4 malabsorption [JAMA, 2000]. TSH normalized after withdrawal of CC. No other similar studies were published.
We wished to test whether an interval of 6 to 8 h between prior ingestion of tablet L-T4 and subsequent ingestion of CC was better than an interval of 1-2 h (60-120 min) to avoid the L-T4 malabsorption caused by CC. We selected 50 women with primary hypothyroidism (age 71.7 ± 5.1 years) based on [i] taking tablet L-T4 and CC, both prior to breakfast, but none of other medications known to alter thyroid function tests; [ii] CC taken within 1-2 h after tablet L-T4 for at least 2 consecutive years; [iii] having had stable serum TSH levels (≤4.12 mU/L) for at least two years when they had taken tablet L-T4 alone. They were instructed to postpone CC by 6 to 8h (per patient's choice) after L-T4. Data are mean ± SD and percentages. Statistics by ANOVA after log10 transformation of TSH, and chi square. Under L-T4 alone, serum TSH was 1.93 ± 0.5 mU/L with no patient having TSH levels above 4.12 mU/L. In contrast, under L-T4 plus CC taken 1-2 h later, TSH was 3.33 ± 1.0 (P < 0.0001) with 9/50 patients (18%, P < 0.01 vs 0/50) having TSH above 4.12 mU/L. Under L-T4 plus CC taken 6-8 h later, TSH was 2.16 ± 0.5 mU/L (P = 0.03 vs L-T4 taken alone; P < 0.0001 vs L-T4 plus CC taken 1-2 h later); though no patient had TSH levels above 4.12 mU/L, 5/50 (10%) failed to do so for just a few decimals. In conclusion, while postponing CC ingestion by 6-8 h after tablet L-T4 works better than postponing by only 1-2 h, nevertheless it is associated with serum TSH levels significantly greater than when L-T4 is taken alone.
Disorders of Thyroid Function Saturday Poster Clinical
The reported prevalence of thyroid disease in pregnancy varies widely. For example, the prevalence of subclinical hypothyroidism in the published literature is 1.5%-42.9%. These discrepancies are mainly due to differences in criteria for euthyroidism, nationality, and gestational age at screening. Currently accepted rates of prevalence for thyroid diseases in pregnancy do not exist. Defining the true prevalence rates has implications for clinical management and the discussion of universal screening. The aims of this study were to assess (i) the actual prevalence of thyroid disorders in pregnancy and (ii) the impact of diagnostic methodology on these rates. A systematic review was conducted of the Pubmed database and references from review articles. Sixty-three studies reporting prevalence in pregnancy of overt hypothyroidism (OHypo), subclinical hypothyroidism (SCHypo), isolated hypothyroxinemia (IH), subclinical hyperthyroidism (SCHyper) and overt hyperthyroidism (OHyper) in pregnant women were included. Studies of hypothyroidism were further classified by the TSH cutoff used for diagnosis: 97.5th percentile, 95th percentile, 2.5 mU/L, or above 4.0 mU/L. Studies of hyperthyroid disease were classified by whether screening was performed in the first or second trimester. Meta-analysis yielded pooled-prevalence rates, with subgroup analyses for TSH cutoff and timing of screening. The 97.5th percentile TSH cutoff was assessed to yield the most accurate prevalence rates. Pooled-prevalence rates for hypothyroidism calculated from studies using the 97.5th percentile as upper limit for TSH were 0.50% for OHypo, 3.47% for SCHypo and 2.05% for IH. Pooled-prevalence rates in the first and second trimesters for hyperthyroidism were 0.91% and 0.65% respectively for OHyper and 2.18% and 0.98% respectively for SCHyper. Population-based, trimester-specific TSH cutoffs (97.5th percentile) for diagnosis of hypothyroid disease in pregnancy provide clear prevalence estimates. Prevalence of hyperthyroidism in pregnancy varies depending on timing of screening. The prevalence rates reported in this study represent the best estimate to date of the true rates of thyroid disease in pregnancy.
Disorders of Thyroid Function Saturday Poster Clinical
Hypocalcemia from transient hypoparathyroidism is the most frequent complication of total thyroidectomy. In adults, immediate postoperative parathyroid hormone (PTH) level of <15 pg/mL indicates increased risk of acute hypoparathyroidism, but pediatric data is limited. Our multidisciplinary pediatric thyroid program started all patients on preoperative oral calcium and calcitriol, which were gradually weaned off based on weekly calcium labs, regardless of post-operative PTH level. To minimize the duration of unnecessary medication and number of lab draws without increasing the risk of hypocalcemia, we implemented a QI project over 6-months. Our new Thyroidectomy without Unnecessary Medication Supplementation (TUMS) protocol eliminated preoperative supplementation, created standardized management of inpatient hypocalcemia through our new multidisciplinary algorithm with quicker calcium and calcitriol wean in patients with one hour postoperative PTH >30 pg/mL (we selected conservative PTH cut-off given limited pediatric data). A prospective cohort managed with the new protocol (TUMS) was compared to a retrospective cohort managed by the prior protocol (No-TUMS). A total of 34 patients had total thyroidectomy from 09/2017 to 07/2018 with median age of 14 [range 3-19]. The most common diagnosis was Graves Disease (52%). In TUMS cohort (n = 17), median duration of calcium therapy was 29 [14, 55] days compared to 49 [4, 179] days in No-TUMS cohort (n = 17). TUMS cohort had a median of 3.5 [2,8] lab draws compared to a 4 [1,10] in No-TUMS cohort. Median post-op calcium level was 8.9 [7.7, 9.7] compared to 8.6 [7.1, 9.1] in TUMS and No-TUMS cohorts, respectively. In TUMS cohort, 70% of patients had postoperative PTH >30 pg/mL. Intravenous calcium use decreased from 18% (3/17) to 12% (2/17) after initiation of TUMS protocol. Symptomatic hypocalcemia in the TUMS cohort was 6% (1/17). Our novel TUMS protocol decreased duration of supplementation and number of lab draws without increasing IV calcium use. This QI project established an infrastructure and strategy for future QI projects at our center to individualize management of calcium supplementation in pediatric thyroidectomy cases based on postoperative PTH level.
Thyroid & Development Saturday Poster Basic
Thyroid hormone stimulates development and homeostasis in many tissues. Evidence indicates that in addition to circulating thyroid hormone, deiodinase enzymes within tissues modify the local level of T3, the active form of hormone. Type 2 deiodinase encoded by Dio2 amplifies levels of T3 by conversion from T4, and promotes for example, auditory development, bone maturation and maintenance of T3 levels in brain. In certain tissues, Dio2-positive cells have been proposed to release T3 to adjacent target cells in a paracrine-like form of control. A limitation in studying type 2 deiodinase is that the protein has a short half-life, is typically at low levels and is often only transiently induced in specialized cell populations. These limitations make it difficult to monitor Dio2-positive cell types with precision. We derived a Dio2-Cre knockin mouse that expresses Cre recombinase from the endogenous Dio2 gene. Dio2-positive cells are revealed by Cre-dependent induction of a readily-visualized fluorescent marker when crossed to Ai6[GFP] reporter mice. We previously reported that Dio2 is induced in the cochlea before the onset of hearing and is essential for auditory development. The Dio2-Cre model clearly identifies Dio2-positive cell types in the spiral ligament in the lateral wall, the septal divisions and central modiolus but not in internal tissues in the organ of Corti. Dio2-positive fibrocytes are located in proximity to blood capillaries, the source of T4 supply, and can extend projections towards the organ of Corti. The results are in accord with paracrine-like control in which T3-generating cell types are separate from T3-responsive cells in the organ of Corti. The Dio2-Cre model overcomes previous technical limitations to allow sensitive and specific detection of Dio2 expression at cellular resolution in vivo. In the cochlea, Dio2-positive cell types reside in vascularized support tissues but not in T3-responsive tissues in the organ of Corti, consistent with a paracrine-like mechanism of control. The model can detect Dio2-positive cells in any tissue of interest, such as pituitary, bone or brain.
Thyroid Cancer Saturday Poster Basic
Thyroid cancer has rapidly increased incidence worldwide. Patients with differentiated thyroid cancer have a better survival while still 10% of cases can develop into more aggressive and dedifferentiated forms of thyroid cancer, leading to recurrent disease and death. There is an unmet need for additional treatment for these refractory and recurrent thyroid cancers. Vitamin C was previously identified as a functional treatment in Braf mutant colon cancers. Considering the comparability between thyroid cancer and colon cancer and abnormal signal modulation such as Braf mutation were the driven force among thyroid cancer progression, we performed a series of experiments and revealed the therapeutical effect of vitamin C on thyroid cancer. MTT assay and cell apoptosis assay were used to evaluate the inhibitory function of vitamin C on thyroid cancer cells in vitro. Xenograft and transgenic mice model were used to test the effect of vitamin C on the thyroid cancer growth in vivo. Molecular experiment such as Western blot, RT-PCR, ELISA and Immunoprecipitation were performed to investigate the mechanism underlying the cancer cell growth inhibition of vitamin C. Pharmaceutical concentration of Vitamin C significantly inhibits the growth of thyroid cancer cell in vitro and in vivo via induction of ROS. Vitamin C selectively deleted the ATP level in Braf mutant cancer. Vitamin C decreased the activities of MAPK/Erk and PI3K/Akt pathway in both BRAF mutant and BRAF wild type thyroid cancer cells. Pharmaceutical concentration of Vitamin C have clinical potential for thyroid cancer therapy
Thyroid Cancer Saturday Poster Basic
It is well known that bidirectional communication between cancer cells and the microenvironment is important for tumor growth. In particular, interaction between cancer cells and stroma cells called fibroblasts have been shown to be crucial for initiation, progression and metastasis in many cancers. While little is known about their interaction in thyroid cancer, this represents a potential alternative treatment target. Our study aimed to create an in vitro cell system to examine the interaction between thyroid cancer cells and fibroblasts. Due to a lack of commercially available human thyroid fibroblast cell lines, we developed a method to culture fibroblast lines from our surgically resected thyroid patient samples. Three primary cell lines were created; two from benign nodules (LS026 & LS029) and one from normal tissue (LS027). They were evaluated to determine whether they were of fibroblastic origin through morphological assessment via bright field microscopy, quantification of αSMA expression by western blot as well as by quantitative real-time PCR (qRT-PCR) for fibroblast markers αSMA, COL1A2, FSP1, FAP1 and CD90. To confirm that the fibroblast cell lines were homogenous, immunofluorescence αSMA staining was performed and quantified as well as qRT-PCR for thyroid markers TG, TPO & TSH receptor. Next, we examined the influence that these fibroblasts had on thyroid cancer cells. Conditioned medium isolated from LS026, LS027 or LS029 was given to three papillary thyroid cancer (PTC) cell lines BCPAP, KTC1 and TPC1 and migration and proliferation assays were performed. All three cell lines were confirmed to be homogenous and of fibroblastic origin. Migration assays showed that there was a statistically significant increase in migration in all three cell lines. Cell viability (WST) assays were performed simultaneously to show that the increase in migration was not due to increased proliferation. Proliferation assays showed that there was a statistically significant increase in cell number after 24 hours in all three cell lines. Altogether, this data suggests that fibroblasts can be isolated from resected thyroid specimens, and secreted factors from these fibroblast effect functions in thyroid cancer cells.
Thyroid Cancer Saturday Poster Clinical
Molecularly targeted therapies are becoming standard of care for patients with advanced metastatic thyroid cancer although response rates are variable, adverse events are common, and treatment is largely palliative. Advancements in next-generation sequencing and their implementation for clinical tumor profiling have identified recurrent driver mutations in thyroid cancer, many of which are now actionable. The adoption of clinical tumor genotyping enables the rapid detection of targets amenable to precision therapy and provides new options for the management of advanced metastatic disease. Formalin-fixed paraffin-embedded tumors from patients with thyroid cancer seen at Massachusetts General Hospital between 2004 and 2018 underwent clinical genotyping using multiplexed allele-specific PCR or targeted next generation sequencing assays and were tested for gene rearrangements using fluorescence in-situ hybridization (FISH) or an anchored multiplex PCR-based targeted fusion transcript assay. A total of 331 patients underwent clinical molecular testing; the median age was 63 years, and 59.6% were female. The most common thyroid cancer subtypes were papillary (64.5%), anaplastic (11.6%), medullary (11.3%), poorly differentiated (11.3%), follicular (5.3%), and Hürthle cell (5.0%). 225 patients (68.0%) had ≥1 molecular alteration including single nuclear variants, copy number variation, and/or gene fusions. Of those testing positive, 214 (95.1%) patients had tumors harboring actionable alterations. The most common mutations were in BRAF (55.1%), RAS (23.8%), RET (12.2%) PIK3CA (4.7%), PTEN (3.3%), TSC2 (2.3%), NTRK (1.7%), ALK (0.9%), AKT (0.9%), and 8.9% of patients harbored fusions involving RET (6.1%), NTRK (1.9%), ALK (0.5%) or ROS (0.5%). A total of 50 patients (23.4%) with actionable molecular alterations received matched therapy. Thyroid cancer genotyping is feasible in a clinical setting, reveals a high number of potentially actionable mutations, and facilitates treatment of patients with advanced disease. Further research is underway to compare the outcomes of patients receiving targeted therapies compared to those receiving the standard of care empiric approach.
Thyroid Cancer Saturday Poster Clinical
Single agent immunotherapy has limited efficacy in thyroid cancer. Combination approaches have been used to increase immunogenicity of tumors and enhance response rates. In a phase II study, ipilimumab (ipi) with SABR to metastatic lesions has shown promising results in different tumor types. Here, we report data on the thyroid cancer expansion cohort part of that trial. Single institution study using sequential ipi (3 mg/kg every 3 weeks for 4 doses) with SABR (50 Gy in 4 fractions or 60 Gy in 10 fractions to metastatic liver or lung lesions). SABR was delivered beginning the week after the second ipi dose. Best response (both irradiated and non-irradiated lesions) was calculated using standard immune related response criteria. Between 2/2016 and 1/2018, 19 pts with thyroid cancer were enrolled; 53% female; median age of diagnosis was 57 years (r: 36-68); 6 differentiated (DTC), 6 poorly differentiated (PDTC), 4 anaplastic (ATC), 3 medullary (MTC). Prior to study entry, all pts had progressive disease (PD) and 8 received ≥1 kinase inhibitor (KI). All pts received ≥1 ipi, 8 (42%) received all 4 ipi, and 15 (79%) received SABR. Immune related stable disease (irSD) was noted in 10/19 (53%) pts (1 ATC, 1 MTC and 8 DTC/PDTC); 9/19 (47%) pts had irPD, of which 4 had irPD prior to SABR (2 ATC, 2 PDTC). Median progression free survival (PFS) was 20 weeks (95%CI 0.0, 41.3) in the entire population and 34 weeks (95%CI 3.7, 64) in pts who completed SABR. Median OS was not reached at median follow up of 32 weeks (95%CI 0, 65). In pts with irSD, median PFS was 71 weeks (95%CI 15.6, 126.4) and they are all alive. In pts with PD on KI: 25% irSD and 75% irPD; median PFS was 9 weeks (95%CI 0.7, 17.3). In KI naïve pts: 73% irSD and 27% irPD; median PFS was 34 weeks (95%CI NR, NR). Five pts discontinued ipi due to toxicity (3 colitis, 1 hypophysitis, and 1 clinical deterioration); all had irSD. Sequential use of ipilimumab with SABR to metastatic lesions shows promise in thyroid cancer by providing durable stable disease. In a subset of patients, this short term treatment approach could replace available chronic therapies. Further investigation is needed to better understand who can benefit from this approach.
Thyroid Cancer Saturday Poster Clinical
Intraoperative neural monitoring (IONM) has gained increasing acceptance as an adjunct to standard practice of visual Recurrent laryngeal nerve (RLN) identification during thyroid surgery. However, the administration of neuromuscular blocking agent (NMBA) might cause unsuccessful monitoring during operation. This prospective study tried to evaluate the feasibility of Sugammadex during thyroid operations. Complete IONM data for 57 patients who had normal cord mobility were investigated: 32 patients received an enhanced NMB recovery protocol—rocuronium 0.6 mg/kg at anesthesia induction and sugammadex 2 mg/kg at the exposure of vagus nerve (group S) and 25 received an induction dose of rocuronium 0.3mg/kg (group R). Electromyography (EMG) signals were obtained from the vagus nerve and RLN before and after resection of the thyroid lobe and were defined as V1, V2 and R1, R2 signals, respectively. The train-of-four (TOF) ratio was used for continuous quantitative monitoring of neuromuscular transmission. V1, V2 and R1, R2 signals were obtained successfully in all patients. The time for tracheal intubation was 102.97 ± 64.5 seconds in group S with high dose rocuronium, while it took 195.12 ± 68.9 seconds in group R (P < .001). In group S, linear relationship was found between EMG amplitudes after surgery and mean amplitudes during surgery. Higher EMG signals were obtained for 31 of 32 patients in 1 minute after administration of Sugammadex. The mean highest amplitude was 1016.8 (95%CI 606, 1427.5) μV at the second minute after administration of Sugammadex under RLN stimulation. The employment of sugammadex for reversal of rocuronium can greatly shorten the tracheal intubation time and reduce the difficulty of surgery under the premise of ensuring the EMG signal intensity. Sugammadex was feasible for IONM during thyroid surgery.
Thyroid Cancer Saturday Poster Clinical
Medullary thyroid carcinoma (MTC) is a neuroendocrine tumor that secretes calcitonin. Preoperative serum calcitonin level reflects the extent of the disease while postoperative calcitonin correlates with residual MTC. The 2 values are established prognostic factors for MTC, yet the prognostic value of the ratio between these 2 values was poorly investigated. This study aims to determine the predictive value of postoperative to preoperative calcitonin ratio (PPCR) of MTC patients. Eighty five patients with MTC who underwent total thyroidectomy and neck dissection between 1984 and 2016 were reviewed retrospectively. We evaluated the prognostic value of PPCR in the follow-up of patients with MTC. The median follow-up duration was 76 months (range 1-399). PPCR significantly correlates with overall survival (OS) (r = 0.303, P = 0.005), disease free survival (DFS) (r = 0.256, P = 0.018) and distant metastases (DM) (r = 0.574, P < 0.001). PPCR had significantly prognostic virtues as demonstrated by ROC plot for OS (AUC = 0.710, P = 0.006), DFS (AUC = 0.669, P = 0.019) and DM (AUC = 0.853, P < 0.001). Cox multivariate survival analysis that included PPCR, preoperative calcitonin and postoperative calcitonin revealed PPCR as the only significant independent factor for OS (P = 0.05). Our results imply PCCR as an efficient widely available and independent prognostic factor for OS, DFS and DM for MTC patients. PCCR may supplement known predictive values in establishing treatment and surveillance strategies for MTC. This factor superiority over the use of preoperative and postoperative calcitonin separately should be farther investigated.
Thyroid Cancer Saturday Poster Clinical
Measuring the quality of health care and utilizing this data is essential to improve delivery of care and surgical outcome. In this context, surgeon volume and subspecialty training have emerged as key determinant of surgical outcomes. We sought to evaluate the association between surgeon specific volume and subspecialty training with regards to avoidable thyroid and parathyroid reoperation.431 thyroid (TR) and parathyroid (PR) reoperations between 2011 and 2017 were evaluated. Indication for initial surgery, indication for reoperation, final histopathology and postoperative outcomes were collected. Following the current standard of care, reoperations were classified as avoidable or unavoidable. Surgeons were classified as high volume (HVS;>50 cases/yr) or low volume (LVS; <50 cases/yr) and by subspecialty training in Endocrine Surgery (ES) or non-Endocrine Surgeon (NES). SPSS v20 was used for statistical analysis. Surgeons operative volume were available for 333 (77%) reoperations. There were 153 referring surgeons with the majority being LVS (80%) and NES (87%). 27% of PR and 24% of TR were avoidable. Persistent primary hyperparathyroidism (53%) and thyroid malignancy (64%) were the most common causes for PR and TR respectively. For PR from LVS, 34% were avoidable compared to 16% for HVS (P = 0.032). For PR from NES, 38% were avoidable compared to 14% for ES (P < 0.005). For TR from LVS, 41% were avoidable compared to 7% for HVS (P < 0.001). For TR from NES, 38% were avoidable compared to 9% for ES (P < 0.001). Recurrent laryngeal nerve injury was more frequent for LVS (7%) and NES (6%) compared to HVS (<1%) and ES (<1%) (P < 0.001 for both). Many TR and PR are avoidable resulting in unjustified cost and morbidity. Most avoidable surgeries originate from LVS or NES. Thyroid and parathyroid surgeries performed by HVS and/or ES decreases the incidence of avoidable reoperations and improve surgical outcomes.
Thyroid Cancer Saturday Poster Clinical
Serum thyroglobulin (Tg) level serves as an important biomarker in the follow-up of differentiated thyroid cancer (DTC) patients. Anti-thyroglobulin antibody (TgAb) influences the measurement of Tg, making it unreliable. Some studies also show that after total thyroidectomy, TgAb gradually declines, while an increase/persistently high levels may indicate cancer persistence/recurrence. However, use of TgAb as a prognostic marker remain controversial. To determine if anti-thyroglobulin antibody is a reliable prognostic marker for differentiated thyroid cancer based on current evidence in the literature.
A comprehensive literature search of studies of DTC patients with known TgAb status and prognostic outcomes were identified through four databases (Medline, Embase, Pubmed and Scopus). Pooled odds ratios and 95% confidence intervals (CI) were calculated using a random-effects model for the association of TgAb status with DTC prognosis. A total of 35 studies were included in the analysis. TgAb+ patients have higher risk of lymph node metastasis (OR: 1.18; 95% CI: 1.47-2.25) and cancer persistence/recurrence (OR: 2.95; 95% CI: 1.65-5.26) compared to TgAb- patients. However, there were no statistical differences in mean/median tumour sizes, risks of extrathyroidal extension, tumour multifocality and cancer mortality between groups. When comparing TgAb trends, patients with persistent/increasing TgAb levels have higher risk of cancer persistence/recurrence (OR: 10.64; 95% CI: 4.60-24.58) and cancer mortality (OR: 15.18; 95% CI: 2.99-77) than patients with decreasing TgAb levels. TgAb positivity and persistent/increasing trend were associated with poor DTC prognosis which suggests the possibility of using TgAb as a prognostic marker in the follow-up of DTC patients especially those who are TgAb positive.
Thyroid Cancer Saturday Poster Clinical
Thyroid Hormone Action Saturday Poster Basic
Phosphorylation is an important mechanism that regulates the function of nuclear hormone receptors. Phosphorylation of thyroid hormone receptors (THRs) has been suggested but its role in hormone action remains unclear. We use mass spectrometry and Phos-tag PAGE to characterize phosphorylation of Thrb2 in a cultured thyrotroph cell line (TαT1.1) and in the mouse pituitary. Kinase inhibitors and RNAi approaches are used to identify corresponding kinase. Expression of endogenous target genes regulated by THRB2 are measured by qRT-PCR. We use EMSA to assess effect of THRB2 phosphorylation on DNA binding. Here we identify a new phosphorylation site in amino-terminus of THR β2 (THRB2). We show that THRB2 is highly phosphorylated both in a cultured thyrotroph cell line (TαT1.1) and in the mouse pituitary, and the level of phosphorylation is increasing in response to TH treatment. We also show that THRB2 phosphorylation is essential for regulation of gene expression at low concentrations of TH, especially for negative regulation of Tshb. Further, we identified a cyclin-dependent kinase, Cdk2 as a key enzyme responsible for THRB2 phosphorylation, and demonstrate that THRB2 phosphorylation reduces homodimer binding and increases heterodimer binding with RXR on DNA.
Our results suggest that phosphorylation affects formation of the THRB2 protein complex on select regulatory elements to ensure a robust response to TH. Our findings also underline a broader role for Cdk2 in thyroid hormone action beyond cell cycle control.
Thyroid Imaging Saturday Poster Basic
According to the consensus of an international study, noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) was proposed as a new thyroid tumor entity to rename non-invasive encapsulated FVPTC. The NIFTP Working Group established a nuclear scoring system for PTC type nuclear features. Shortly after introduction, NIFTP was included in the newly introduced group of borderline thyroid neoplasms in the new WHO classification. The standardized nuclear scoring system and absence of the capsular/vascular invasion and high-grade histologic features are the key points for a correct diagnosis of NIFTP. This study was conducted to evaluate the current diagnostic criteria in reporting nuclear features of NIFTP in Asian practice. Nine Asian endocrine pathologists reviewed virtual slides of 30 non-invasive follicular patterned thyroid lesions according to the nuclear scoring system originally proposed by an international expert working group and a more detailed scoring system proposed by the Asian working group. The interobserver agreement for nuclear grading score of NIFTP was generally moderate (kappa value = 0.452). The best consistency fell on the chromatin features (kappa value = 0.658–1.000). Fair to a moderate interobserver agreement was demonstrated in the evaluation of nuclear elongation, nuclear overlapping, membrane irregularities and distribution of papillary thyroid carcinoma type nuclear features. A slight agreement was rendered for the evaluation of the nuclear enlargement. Intraobserver agreement was substantial to perfect when comparing results of both scoring systems. However, both scoring systems were not able to reliably separate NIFTP from a follicular variant of papillary carcinoma with minimal lymph node metastasis orBRAF V600Emutation. Although the 3 points nuclear scoring system for the diagnosis of NIFTP is widely used in Asian practice, interobserver variation was considerable. Ancillary immunohistochemical or molecular testing might be helpful in differentiating NIFTP from true papillary thyroid carcinoma.
Thyroid Nodules & Goiter Saturday Poster Case Report
Cytologically indeterminate thyroid nodules with Hürthle cells pose cytological and molecular challenges. Two Hürthle classifiers interface with the core GSC classifier to assess every FNA. We investigated how they performed among Bethesda III, GSC Suspicious nodules that were negative for mutations and fusions in a large RNA panel [the Xpression Atlas (XA)]. The Hürthle index (HI) classifier determines if the specimen contains Hürthle cells. If HI is negative, then the core GSC classifier renders a benign or suspicious result. If HI is positive for Hürthle cells, then the Hürthle neoplasm Index (NI) classifier determines if the specimen is neoplastic. If neoplastic, then the core GSC classifier renders a benign or suspicious result. However, if NI is negative for neoplasia, then the core GSC classifier uses an adjusted threshold that allows more GSC benign results.
Cleveland Clinic samples submitted for GSC testing were reviewed with Veracyte to identify all that were Bethesda III, GSC Suspicious, HI positive, NI positive, and XA negative. Two cases were identified. Case 1. Initial FNA = AUS. Hürthle cells with cytologic atypia and background lymphocytes. [cytology comment: In a patient with Hashimoto's thyroiditis, this may represent Hürthle cell hyperplasia. Hürthle cell neoplasm cannot be entirely exclude.] No GSC submitted. Repeat FNA = AUS. Predominant oncocytic population. Minimal colloid. [cytology comment: Differential diagnosis includes hyperplastic oncocytic nodules vs oncocytic neoplasm.] GSC Suspicious, XA negative. Surgical histology: 2.3 cm PTC, oncocytic variant.
Case 2. Initial FNA = AUS. Hürthle cells with some background lymphoid cells. [cytology comment: In the right clinical context, this raises the possibility of lymphocytic thyroiditis.] GSC Suspicious, XA negative. Surgical histology: 0.9 cm PTC, oncocytic variant and chronic lymphocytic thyroiditis. In both cases the HI and NI classifiers were correct given the Hürthle cell cytology and neoplastic surgical histology, respectively. The presence of malignancy, despite the lack of mutation or fusion on the 511 gene Xpression Atlas, supports that the GSC has high sensitivity, despite its significantly increased benign call rate.
Thyroid Nodules & Goiter Saturday Poster Clinical
Metabolomics provides valuable information about metabolism of malignant cells and has a potential in cancer diagnosis. Although such studies on thyroid tumors are scarce in the literature.
This study is aimed to explore thepotential use of Proton Magnetic Resonance Spectroscopy to identify specific metabolic signatures for various pathologicalthyroid lesions. After obtaining clearance from Institutional Ethics Committee,100 freshthyroid tissue and serum samples (50 benign and malignant each) were obtained from patients operated for variousthyroid pathologies at the Department of Endocrine Surgery, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow (India) from Jan 2016 to Aug 2017. Specimens were snap frozen and transported to laboratory in liquid nitrogen cylinder for spectroscopicanalysis. Metabolic profiles were statistically generated based on the spectroscopy results, using MetaboAnalyst 4.0which were then correlated with histology. The discriminant version of the Partial Least Squares regression (PLS-DA) was used to evaluated difference between the groups with a seven fold cross validation. Various Potential biomarkers common to all thyroid lesions were identified. The Partial Least Square Discriminant Analysis (PLSDA) analysis for serum as well as tissue samples revealed a good separation of the healthy (H) vs malignant (M) as well as healthy vs benign (B) along with good model significance. Malignant vs benign predictive potential was better in tissue than serum samples. Within benign class the colloid Nodule (CN) vs Follicular Adenoma (FA) separation did not pass the model significance in both serum as well as tissue samples. CN vs M discrimination was good in serum as well as tissue but the predictive potential was better in tissue. FA vs M discrimination model showed very poor model significance for both kind of samples.
The results indicate the potential of proton magnetic resonance spectroscopy as an ancillary molecular marker in diagnosis of cancer and differentiating it from benign conditions of thyroid.
Thyroid Nodules & Goiter Saturday Poster Clinical
Thyroid ultrasound is crucial for clinical decision in the management of thyroid nodules. In this study we aimed to estimate and compare the performance of ATA (American Thyroid Association), AACE/ACE-AME (American Association of Clinical Endocrinologists) and TI-RADS (Thyroid Imaging Reporting and Data System) ultrasound classifications in discriminating nodules with malignancy histology. We conducted an observational and retrospective study. From January to June 2018, 505 thyroid nodules in 421 patients (mean age 54.5 ± 14.7 years, 86.7% female) were included in this study. Characteristics including size, composition, shape, margin, echogenicity, calcifications and extrathyroidal extension of thyroid nodules were evaluated. Thyroid nodules were stratified according to ATA, AACE and TIRADS ultrasound classification and malignant rate of each risk stratification were calculated and analysed. Of the 505 nodules, 10 (2%) were malignant. One hundred and eighty-nine (37.4%) did not meet the criteria for the ATA patterns and where classified as “not specified”. The mean size of nodules were 1.9 ± 1.1 × 2.1 ± 1.4 cm. The malignancy rates under TIRADS category 2,3, 4 and 5 were 0%, 0%, 1.2% and 3.1%. Malignancy rates under ATA guidelines of benign, very low, low and intermediate were 0%, while malignancy rate of high suspicion was 5.2% and of “not specified” was 0.4%. Malignancy rate under AACE guidelines of low-risk lesion, intermediate-risk thyroid lesion and high-risk thyroid lesion were 0%, 0.6% and 2.1%, respectively. There were significant differences inside each patterns (p < 0.03). There was high correlation between classification TIRADS (r = 1.000), ATA (r = 0.912) and AACE guidelines (r = 0.853). Areas under the ROC curve of TIRADS, ATA and AACE were 0.816, 0.779 and 0.762, respectively. Best cut-off point for diagnosing malignant by TIRADs, ATA and AACE were TIRADS 5, high suspicion and high-risk thyroid lesion, respectively. At that point sensitivity and specificity of guidelines were nearly the same and there was no significante difference (p > 0.05). In conclusion, TIRADS, ATA and ACE guidelines provide effective malignancy risk stratification for thyroid nodules.
Thyroid Nodules & Goiter Saturday Poster Clinical
The risk of thyroid cancer in large thyroid nodules greater than 4 cm has been reported to be increased. Some authors suggest that diagnostic thyroidectomy should be performed in patients with large thyroid nodules, irrespective of fine needle aspiration cytology (FNAC) results. However, consensus on that matter has not been met. We wanted to investigate the risk of thyroid malignancy according to the size of the thyroid nodules, based on FNAC results. We conducted an observational and retrospective study, that included patients submitted to FNAC of thyroid nodules from January to June 2018 at our institution. Four hundred and sixty-six FNAC results of 421 patients with thyroid nodules (mean age 54.5 ± 14.7 years, 86.7% female) were evaluated according to the size category. The nodules were categorized to four groups by maximal diameter of the nodule on ultrasonography (Group A 1-1.9 cm; Group B 2-2.9 cm; Group C 3-3.9 cm; Group D ≥ 4 cm). Number of patients in group A, B, C and D were 282, 110, 54 and 20. The mean sizes of the nodule in each group were 1.5 ± 0.3 cm, 2.3 ± 0.4 cm, 3.4 ± 0.3 cm and 4.6 ± 1 cm, respectively. Based on Thyroid Imaging Reporting and Data System (TIRADS) classification, highly suspicion nodules (TIRADS 5) in each group were 128 (45.4%), 39 (35.5%), 10 (18.5%) and 6 (30.0%). After FNA, the Bethesda system 4-6 categories were reported in 7 thyroid nodules (2.5%) on group A, 1 thyroid nodule on group B (0.9%) and 2 thyroid nodules on group C (3.7%), in each group there was no increased risk of malignancy in larger thyroid nodules (p = 0.051). In our experience, large thyroid nodules (≥4 cm) are not at higher risk for malignancy. The medical decision for thyroid surgery should be guided by the clinical presentation, nodule ultrasound characteristics, FNAC results and not only by the size of the nodule.
Thyroid Nodules & Goiter Saturday Poster Clinical
The American College of Radiology (ACR) has recently proposed a guideline that recommends clinicians to perform thyroid fine needle aspiration cytology (FNAC) on the basis of ultrasound features. In this study, we focused on nodules for which no cytology is recommended by the Thyroid Imaging, Reporting and Data System (TIRADS) guideline. Two-hundred and sixteen thyroid nodules in one-hundred and eighty patients (mean age 54.5 ± 14.7 years, 84.5% female) with thyroid nodules who underwent FNAC according to the 2015 American Thyroid Association (ATA) guideline were included. The nodules were re-classified according to the TIRADS guideline as benign (TIRADS 1), not suspicious (TIRADS 2), mildly suspicious (TIRADS 3), moderately suspicious (TIRADS 4) and highly suspicious (TIRADS 5). Forty-two thyroid nodules (19.4%) with non-diagnostic FNAC were excluded. When the TIRADS 1, TIRADS 2, TIRADS 3 < 2.5 cm and TIRADS 4 < 1.5 cm categories were merged, FNAC was no suggestive of thyroid cancer (n = 48). FNAC didn't revealed Bethesda IV-VI patterns in 14 patients with the TIRADS 3 nodules with diameter of 2.5cm or more. FNAC revealed Bethesda V in 1 of 58 of patients with the TIRADS 4 (1.7%) nodules with diameter of 1.5cm or more. The histological diagnosis of that nodule was papillary thyroid carcinoma. FNAC revealed Bethesda IV and VI in 2 of 54 of patients with the TIRADS 5 category (3.7%), with histological diagnosis of papillary thyroid carcinoma. The TIRADS accuracy diagnostic estimated by ROC curve was 0.770. The TIRADS scoring was 95.1% specific for identification of a benign nodule. Our data suggest that TIRADS scoring is an applicable and potentially cost-effective approach to determine thyroid nodules to be perfomed a cytology.
Thyroid Nodules & Goiter Saturday Poster Clinical
Percutaneous ethanol injection therapy (PEIT) is a minimally invasive method which can be preferred in treatment of cystic thyroid nodules, as an alternative to surgery or repetitive simple aspiration. The aim of this study is to evaluate the efficacy and safety of PEIT. The PEIT was performed under ultrasound guidance and 96% ethanol was injected into the the cyst in an amount that is 30-50% of the cystic fluid extracted. We conducted an observational and retrospective study, that included patients submitted to PEIT at our institution. Twenty one patients were included, being 81.0% of the female gender, with a mean age of 51.9 ± 16.4 years. In ultrasonography evaluation, 76.2% of the thyroid nodules were predominant cystic and 23.8% cystic pure. All the nodules had a benign cytology. During the study, patients remained euthyroid. Mean initial cyst diameter was 3.4 ± 1.5 × 3.1 ± 1.1 cm and mean extracted liquid volume 58 ± 36 mL. A single session of PEIT was required to complete the procedure in 85.7% (n = 18) of patients and two in 14.3% (n = 3). After 6.5 ± 6.7 months follow-up, cysts were reduced 58.6% (range 26.7-82.4%) (p < 0.05) in transversal diameter and 53.4% (range 28-82.9%) (p = 0.01) in anteroposterior diameter. Final mean maximum cysts diameter was 1.3 ± 0.7x 1.5 ± 0.8 cm. No complications of PEIT were observed. In patients with compressive symptoms they have disappeared in 77.8% and favorable cosmetic results were seen in 90.5% of patients treated with percutaneous etanol injection. Our first report shows that PEIT is an effective and non-expensive way of treatment for benign cystic and mixt thyroid nodules without any serious side effects.
Thyroid Nodules & Goiter Saturday Poster Translational
DICER1 encodes an endoribonuclease involved in microRNA maturation and therefore has an important role in gene transcript regulation. Germline mutations scattered along DICER1 are associated with DICER1 syndrome which prominently features thyroid nodules. The tumors typically carry a second, somatic mutation in the RNase IIIb catalytic domain, referred to as “hotspot.” These hotspot mutations occur in ∼1-2% of thyroid papillary carcinomas (PTC). The incidence of the hotspot mutations in thyroid nodules in adults, their association with malignancy and with other, germline DICER1 mutations remain largely unknown. We analyzed 6,734 consecutive clinical FNA samples from typically indeterminate cytology thyroid nodules for hotspot DICER1mutations using ThyroSeq v3 targeted next generation sequencing (NGS) assay from 11/2017-05/2018. Available follow-up was collected. A subgroup of cases underwent full DICER1 coding region and exon-intron boundaries analysis using a custom Fluidigm Access Array followed by NGS on Illumina MiSeq. Somatic DICER1 hotspot mutations were identified in 135 (2.0%) of nodules, with D1810H/V/Y and D1709G/E/N being most common. Median patient age was 37 years (range 19-79 y), 93% were females. Follow-up was available for 27 patients: 15 underwent surgery with benign diagnoses in 9 cases, NIFTP in 5 and follicular variant PTC in 1. Twelve patients were managed non-surgically, including one with a stable nodule harboring DICER1mutation at an allele frequency unchanged over 10 years between FNAs. A subset of 11 positive cases was tested for alteration in the entire DICER1 gene, which confirmed the hotspot mutations in 10 and detected additional alterations in 9 (90%), including non-hotspot mutations in 8 and LOH in 1 case. We report for the first time that likely somatic hotspot DICER1 mutations are relatively common and found in ∼2% of thyroid nodules in adults, who are typically mid-age women. At surgery, most of these nodules are benign, with ∼33% risk of NIFTP and ∼7% risk of follicular variant PTC. Our analysis also shows that somatic hotspot mutations are usually accompanied by a second, loss of function DICER1 mutation, which may in some cases be germline in nature.
Thyroid Cancer Saturday Poster Translational
The SPOP gene encodes an E3 ubiquitin ligase adaptor, which binds to its substrates via the MATH domain. SPOP mutations affecting the MATH domain, most commonly SPOP F133C, were found in several cancers types including single cases of papillary thyroid carcinoma (PTC) that carried SPOP P94R mutation. The frequency, distribution, and phenotypical features of thyroid tumors associated with SPOP mutations have not been systematically studied. We analyzed 317 PTC, 41 follicular thyroid carcinomas, 36 Hürthle cell carcinomas, 29 follicular adenomas (FA), 34 Hürthle cell adenomas, 19 poorly differentiated/anaplastic carcinomas and 114 hyperplastic nodules (HN) using Sanger sequencing for mutations in SPOP P94R (exon 2) and F133C (exon 6). Positive cases were genotyped for all common molecular alterations found in thyroid cancer by NGS and also analyzed by RNA-Seq. The effects of SPOP P94R mutation on signaling were studied by western blot and on cell proliferation by MTT assay. SPOP P94R mutation was identified in 5/317 (1.6%) PTC and 2/29 (6.8%) FA and in none of the other tumors or HN studied. The SPOP F133C mutation was not found. Among 4 tumors histologically diagnosed as PTCs with pathology slides available for review, all were encapsulated, 3 (75%) had follicular variant or NIFTP features, and 2 (50%) had peculiar adipose metaplasia. Among two follicular adenomas, one was a rare type of FA that also had papillary hyperplasia. Tumors harboring SPOP P94R mutation had no BRAF, RAS, or other known driver mutations or fusions. By RNA-Seq analysis, all tumors had a RAS-like score. Expression of SPOP P94R but not SPOP WT in HEK293 cells showed activation of the MAPK and PI3K/AKT pathways by western blot and a significant increase in proliferation of HTori-3 thyroid cells. Our results indicate that SPOP P94R but not SPOP F133C mutations occur in encapsulated follicular variant PTC that frequently have adipose metaplasia and in FA, including those with papillary hyperplasia. This mutation likely represents a new driver mutation in thyroid tumors as it does not overlap with other known mutations and results in activation of carcinogenic signaling pathways and increase proliferation of thyroid cells in vitro.