Specificity: Hepatocyte Specific Antigen, also called Hepatocyte Paraffin 1 or Hep Par 1, localizes to the mitochondria of hepatocytes. It is a sensitive marker for distinguishing hepatocellular carcinomas (HCC) from other metastatic carcinomas as well as cholangio-carcinomas. Immunogen: Extract of a formalin-fixed, rejected allograft of a human liver