Expression of ABH and lewis blood group antigens in combined hepatocellular‐cholangiocarcinoma. Possible evidence for the hepatocellular origin of combined hepatocellular‐cholangiocarcinoma

Expression of ABH, Lewis, and sialyl Lea antigens was studied in five combined hepatocellular‐cholangiocarcinomas. Formalin‐fixed liver tissues were immunostained for those antigens using well‐characterized monoclonal antibodies and an avidin‐biotin‐peroxidase complex (ABC) method. Results were compared with those obtained in normal liver tissues and cholangiocarcinomas, and also with the previous observations of the authors on hepatocellular carcinomas. Although not detected in normal parenchymal liver cells, A, H, Lewis, and sialyl Lea antigens were found in combined hepatocellular‐cholangiocarcinoma cells. Incompatible A antigen also was detected in one blood type O patient. Distribution and intensity of the antigens were similar to those in hepatocellular carcinomas and different from those in cholangiocarcinomas. No preferential accumulation of blood‐group antigens could be found in the area of cholangiocarcinoma‐like differentiation of the combined hepatocellular‐cholangiocarcinoma. The observations suggested that. 1 Regional morphological differentiation of the hepatocellular‐cholangiocarcinoma might not be always associated with the change in the expression of the blood group antigens. Moreover, the expression was essentially the same between the hepatocellular‐cholangiocarcinoma and the typical hepatocellular carcinoma. 2 The hepatocellular‐cholangiocarcinoma, therefore could be a variant of the hepatocellular carcinoma.