Hepatocyte Specific Antigen

Hepatocyte specific antigen (HSA), also known as Hep Par 1, is a monoclonal antibody that can specifically label carbamoyl phosphate synthase 1 in liver cell mitochondria. HSA has become an essential diagnostic indicator for hepatocellular carcinoma (HCC), and it is almost not expressed in metastatic liver cancer, which makes it useful for assisting in identification. However, HSA can be expressed in benign liver lesions and hepatoid tumors, so it needs to combine with other biomarkers. For example, HSA can distinguish between HCC and intrahepatic cholangiocarcinoma combined with CD34 and Glypican-3. Moreover, the expression level of HSA is positively correlated with the differentiation degree of HCC, and its low expression or even absence suggests high tumor malignancy. In addition, HSA is expressed in some cervical cancers and is believed to be associated with poor prognosis of patients, which may be because cancer cells abnormally acquire the positive phenotype due to the genetic instability in the early stages. The positive rate of HSA in poorly differentiated gastric cancer is also found to be higher than that in highly differentiated cancer.