Tissue polypeptide antigen--a marker antigen differentiating cholangiolar tumors from other hepatic tumors.

Twenty-two cases of primary hepatic tumors consisting of 11 hepatocellular carcinomas, 6 cholangiocarcinomas, 3 mixed hepatocellular and cholangiocellular carcinomas, and 2 biliary cystadenocarcinomas together with 8 cases of metastatic adenocarcinoma from various sites were studied by immunoperoxidase technic to demonstrate tissue polypeptide antigen. All of the tumors presumably derived from the epithelial lining of the bile duct, including cholangiocarcinoma, cholangiocarcinomatous portion of the mixed hepatocellular and cholangiocellular carcinoma, and biliary cystadenocarcinoma showed strong positive reaction. The hepatocellular carcinoma and the metastatic adenocarcinoma exhibited negative to weakly positive reactions. These results indicate that TPA can be of use in differentiating bile duct carcinomas from hepatocellular carcinoma and, to a lesser extent, from hepatic metastases of various adenocarcinomas.