Abstract
Introduction
SCCA1 and SCCA2 belong to the family of serine protease inhibitors (SERPIN). Both SCCA isoforms have been found to be increased in patients with squamous cell carcinoma (SCC) of different organs. Recent findings have demonstrated that SCCA-IgM immune complexes are a novel class of biomarkers for primary liver cancer detection. An increase in SCCA-IgM levels in patients with cirrhosis is associated with the development of liver cancer.
Aims and methods
To evaluate the diagnostic accuracy of different isoforms of SCCA-IgM compared with a commercial assay for SCCA-IgM in patients with hepatocellular carcinoma (HCC). Twenty-six patients with HCC (M/F 1 9/7; mean age ± SD: 65 ± 13 years) were analyzed. Serum samples from 28 blood donors (M/F 17/11; mean age ± SD: 38 ± 9 years) were used as control. Two monoclonal antibodies, SCC 111 and SCC 1 04 (CanAg Diagnostics, Gothenburg, Sweden) were used as catcher antibodies to perform specific ELISA for SCCA1-lgM and SCCA2-lgM. SCCA-IgM immune complexes were also detected in serum by a commercial ELISA kit (Hepa-IC, Xeptagen, Marghera, Italy) according to the manufacturer's instructions.
Results
Circulating SCCA1-IgM was detectable in 6 out of 26 patients (sensitivity 23%), while SCCA2-lgM ELISA was positive in 9 of 26 patients (sensitivity 35%). When SCCA-IgM levels were measured using the commercial assay the diagnostic sensitivity increased to 58% (15/26). The SCCA1-IgM, SCCA2-lgM and SCCA-IgM tests had 100% specificity in healthy controls.
Conclusions
The commercial assay allowed the detection of both isoforms of SCCA forming the IgM immune complexes, providing a better diagnostic sensitivity score than that obtained with the SCCA1-IgM or SCCA2-lgM test.