Cancer Biomarkers

To determine the usefulness of brain-derived neurotrophic factor (BDNF) as a diagnostic biomarker for colorectal cancer (CRC).

ELISA immunoassay was used to examine BDNF concentrations in the sera of two different retrospective cohorts consisting of CRC patients and age/gender matched controls. Cohort 1 consisted of 99 controls and 97 CRC patients, whereas cohort 2 consisted of 47 controls and 91 CRC patients.

In cohort 1, the median concentration of BDNF was significantly (p< 0.0001) lower in CRC patient samples (18.8 ng/mL, range 4.0–56.5 ng/mL) than control samples (23.4 ng/mL, range 3.0–43.1 ng/mL). This finding was validated in an independent patient cohort (CRC patients: 23.0 ng/mL, range 6.0–45.9 ng/mL; control patients: 32.3 ng/mL, range 14.2–62.4 ng/mL). BDNF concentrations did not differ significantly between Dukes’ staging in the patient cohort, however patients with Stages A, B, C and D (p< 0.01 for each stage) tumours had significantly reduced BDNF levels compared to healthy controls. Receiver operating characteristic analysis was performed to determine the ability of BDNF to discriminate between healthy controls and those with CRC. At 95% specificity, BDNF concentrations distinguished CRC patients with 25% and 18% sensitivity, respectively, in cohorts 1 and 2 (cohort 1: AUC=0.79, 95% CI 0.70–0.87; cohort 2: AUC =0.69, 95% CI 0.61–0.76).

The serum levels of BDNF were significantly lower in colorectal cancer patients when compared to a control population, and this did not differ between different Dukes’ stages.

Lipocalin 2 has been implicated in colorectal tumorigenesis but its usefulness as a diagnostic marker for the disease has previously never been determined.

We have used ELISA immunoassay to measure the level of serum lipocalin 2 in a cohort consisting of colorectal cancer patients (n=196) and age/gender matched controls (n=99).

The median concentration of lipocalin 2 was found to be significantly higher (p< 0.0001) in the patient group (105.9 ng/mL, range 10.8–444.7 ng/mL) when compared to the control subjects (86.4 ng/mL, range 17.1–190.0 ng/mL). Additionally, no significant difference was observed between disease stage (Dukes’ or T stage) in the patient cohort. Receiver operating characteristic analysis was performed to determine its performance as a diagnostic marker. The area under the curve was found to be 0.641 (95% confidence interval 0.576–0.706). Furthermore, the sensitivity of lipocalin 2 was found to be 24% at 90% specificity.

Our study indicates that lipocalin 2 is not a suitable serum biomarker for the diagnosis of CRC.

ABCG2 is a member of the ATP binding cassette (ABC) transporter superfamily and identified to play an important role in multidrug resistance in many studies. But the expression of ABCG2 is controversial in many kinds of tumors including colorectal cancer (CRC).

To clarify the expression patterns of ABCG2 and elucidate the prognostic value of ABCG2 in CRC.

ABCG2 expression was analyzed in 225 primary CRC tissues using immunohistochemical assessment. Cytoplasmic and membranous immunoreactivity were semiquantitatively scored and correlated with clinicopathological variables. 69 cases were used for survival analysis. χ 2 test for trends, Kaplan-Meier analysis and Cox’s regression were used for statistical analysis.

83.1% cases showed positive cytoplasmic expression including 13.3% strongly positive. 66.2% showed positive membranous expression including 15.6% strongly positive. 50% normal mucosa exhibited a strong membranous staining on the apical membrane. The strongly membranous staining significantly correlated to lymph node and distant metastasis. While the cytoplasmic expression levels of ABCG2 protein were only correlated with tumor stage. Survival analysis showed strongly membranous ABCG2 staining correlated to shortened patient survival than negative one (HR=2.439, 95%CI 1.053–5.650, P=0.038), but not cytoplasmic ABCG2 staining.

Our results showed that membranous ABCG2 expression was significantly associated with Dukes’ stage, lymph node metastasis and distant metastasis. However, cytoplasmic ABCG2 expression was only significantly associated with Dukes’ stage.

Strong membranous ABCG2 staining is a potential new independent prognostic factor of CRC. Further studies are needed to clarify the role of ABCG2 in colon carcinogenesis.

The analysis of KRAS mutations in colorectal cancer (CRC) has made the need urgent for a reliable and easy to implement assay in daily practice.

This study was designed to compare the different assays for KRAS testing and elucidate its mutation status in Chinese CRC patients.

Direct sequencing was conducted to detect mutations in KRAS codons 12, 13 and 61 using 574 colorectal paraffin embedded clinical samples. And a subset of 66 samples was further detected independently by a commercial kit for comparison of different assays.

KRAS codons 12 and 13 mutations were detected in 40.9 and 42.4% of 66 CRC samples using the kit and direct sequencing methods, respectively. The concordance between two methods reached 95.5% (Kappa=0.907, P < 0.001). Workload and time to results were comparable for both. Moreover, KRAS mutations were detected in the total 574 CRC tumors by direct sequencing as followed: 25.3% in codon 12, 6.8% in codon 13, and 2.1% in codon 61. Notably, the mutations were more frequent in females than males, and patients older than 60 years exhibited higher rates of mutation (P < 0.05).

Direct sequencing showed similar mutation rate as the detection kit and hence can be used effectively and reliably for clinical screening of somatic tumor gene mutations.

Several serum biomarkers such as antigens, soluble proteins, metabolites, and genes have been identified for the diagnosis of cancers and for monitoring the recurrence after cancer treatment.

In the present study, a protein kinase C (PKC) α-specific peptide substrate was phosphorylated with serum samples collected from cancer-bearing mice (U87, A431, HepG2, and A549) and the phosphorylation ratio was detected by matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS).

The phosphorylation ratio for peptide substrates significantly increased in the serum of cancer-bearing mice compared with the ratio found in control mice. The addition of a PKCα inhibitor induced a concentration-dependent decrease in phosphorylation ratios, but the non-PKCα inhibitors, rottlerin and H-89, did not significantly effect phosphorylation ratios.

These results suggest that serum activated PKCα is a good biomarker applicable to cancer diagnosis.

The aim of this study was to quantitatively assess the impact of VEGF overexpression on prognosis in patients with esophageal cancer (EC).

A meta-analysis was performed on studies reporting overall survival (OS) or clinicopathological parameters to compare the outcomes of EC patients with VEGF overexpression to the outcomes of patients without VEGF overexpression.

There was a significantly increased risk for patients with VEGF overexpression to have an advanced stage of the disease (III and IV) with an odds ratio (OR) of 2.14. Additionally, patients with VEGF overexpression had a 2.03-fold increased risk for distant metastasis and shorter OS (HR=1.55).

VEGF overexpression is associated with a more advanced TMN stage and shorter OS in EC patients.

The aim of this study was to investigate the methylation status of three cell adhesion-related genes including CDH1, TSLC1 and TIMP3 in non-small cell lung cancer and explore its association with clinicopathologic features and various environmental risk factors.

We detected the aberrant methylation presence of these genes by methylation-specific polymerase chain reaction and analyzed the potential correlations with multivariate logistic regression model as well as stepwise logistic regression.

For CDH1, promoter methylation was less frequent in adenosquamous carcinomas than adenocarcinomas (OR=0.35, 95%CI=0.13–0.96); pickled food increased the methylation frequency (OR=2.23, 95%CI=1.09–4.54) while light smoking and fruit intake decreased that (OR=0.43, 95%CI=0.19–0.97; OR=0.37, 95%CI=0.15–0.95). For TSLC1, males and toxin exposure increased methylation frequency (OR=6.25, 95%CI=1.05–37.13; OR=2.42, 95%CI=1.01–5.77) while light smoking and radiation exposure decreased that (OR=0.14, 95%CI=0.03–0.60; OR=0.17, 95%CI=0.04–0.87). For TIMP3, males showed lower methylation frequency than females (OR=0.18, 95%CI=0.04–0.88) while central lung cancer, heavy smoking and radiation exposure presented higher aberrant DNA methylation status (OR=2.19, 95%CI=1.07–4.52; OR=6.99, 95%CI=1.32–37.14; OR=2.30, 95%CI=1.04–5.08).

Aberrant promoter methylation of cell adhesion-related tumor suppressor genes in lung cancer displayed varieties of gene-specific correlations with clinicopathologic features and various environmental risk factors.

We aimed to investigate the concentration of CYFRA 21-1, NSE and CEA in cerebro-spinal fluid (CSF) and to explore their clinical value in the meningeal carcinomatosis (MC) of lung cancer. So that, sensitive and specificity of CSF examination can be improved in the initial diagnosis of MC.

A total of 35 lung cancer patients and 35 patients with benign brain tumor in the same period enrolled in this study. The concentrations of tumor markers CEA, CYFRA 21-1 and NSE in CSF and peripheral blood were examined.

The concentrations of three tumor markers of CYFRA 21-1, NSE and CEA in blood serum and CSF were obviously higher than that of benign disease group. In MC patients, the concentrations of three tumor markers of CYFRA 21-1, NSE and CEA in blood serum were significant lower than that in CSF. The maximum of Youden’s index was identified as the cutoff value of indicator of MC in three tumor markers in CSF which were CEA > 4.7 μg/L, NSE > 14.6 μg/L and CYFRA21-1 > 5.5 μg/L respectively. Based on the cutoff values, the CEA had the highest sensitivity while the CYFRA21-1 had the highest specificitiy. Three tumor markers in the CSF had higher positive rate than those in blood serum. We combined the levels of CEA, NSE and CYFRA21-1 in CSF to diagnosis of MC. Positive of CEA or CYFRA21-1 had the greatest sensitivity of 100% while the specificity of 91.4%; the positive of both CEA and CYFRA21-1 had the highest specificity of 100% while the sensitivity of 74.3%. Both positive predictive value and negative predictive value were 100% when combination positive were confirmed when the all three markers were positive.

The combination of CEA and CYFRA21-1 can be recommended in early screening of meningeal carcinoma. Especially, for the patient who was difficult to be diagnosed by CSF histology and MRI, it will be a useful auxiliary marker in diagnosis of MC. The combination of CEA, NSE and CYFRA21-1 can be an effective clinically confirmation and exclusively diagnose indictor of MC.