Role of SERPINB3 in hepatocellular carcinoma

SERPINB3 (formerly known as squamous cell carcinoma antigen-1 or SCCA1) is a member of the family of serine-protease inhibitors. SERPINB3 protects cells from oxidative stress conditions, but in chronic liver damage this serpin may lead to hepatocellular carcinoma through different strategies, including inhibition of apoptosis, induction of epithelial to mesenchymal transition and decrease of desmosomal junctions, cell proliferation and invasiveness. SERPINB3 may also contribute to tumor cell resistance to anti-neoplastic drugs through its binding to the respiratory Complex I, protecting cells from the pro-oxidant action of chemotherapeutic agents. Mechanisms of tumor growth promotion induced by SERPINB3 include the inhibition of intratumor infiltration of natural killer cells, up-regulation of Myc oncogene and the recent identification of this serpin as a Ras-responsive factor. In the liver SERPINB3 and SERPINBB4 isoforms (known as squamous cell carcinoma antigen or SCCA) are undetectable in normal hepatocytes, but their expression progressively increases in chronic liver diseases, dysplastic nodules and hepatocellular carcinoma. High SERPINB3 levels have been recently detected in HCC tissue of patients with early tumor recurrence after surgical resection. In serum SERPINB3/4 isoforms (or SCCA) are detectable bound to IgMs (SCCA-IgM) in the majority of HCV infected patients with HCC and in patients with cirrhosis their levels and/or the progressive increase have been found correlated to the risk of HCC development. Preliminary findings in patients with HCC revealed that SCCA-IgM was predictive of HCC prognosis, since low levels of this biomarker were able to identify HCC patients with long overall and progression-free survival.