摘要Hepatocellular carcinoma (HCC) is one of the most relevant sanitary problems for its prevalence and poor prognosis. This tumor is characterized by highly heterogeneous features, both at clinical and molecular level. SerpinB3 (squamous cell carcinoma antigen-1 or SCCA1) is a serine-protease inhibitor that protects cells from oxidative stress conditions, but in chronic liver damage it may lead to HCC through different strategies, including inhibition of apoptosis, induction of epithelial to mesenchymal transition, cell proliferation and invasiveness. Mechanisms of tumor growth promotion induced by SerpinB3 encompass the inhibition of intratumor infiltration of natural killer cells and the up-regulation of Myc oncogene. Recently this serpin has also been identified as a Ras-responsive factor and modulator of metabolic pathways. In the liver SerpinB3 is undetectable in normal hepatocytes, but its expression progressively increases in chronic liver diseases, dysplastic nodules and hepatocellular carcinoma, especially in those with poor prognosis, in which it could also exert immunomodulatory effects. In serum SerpinB3/4 isoforms (or SCCA) circulate bound to IgMs (SCCA-IgM) in patients with HCC, and in patients with cirrhosis their levels have been found correlated to the risk of HCC development. Preliminary findings in patients with HCC revealed that SCCA-IgM levels are predictive of HCC prognosis.