Distribution of alpha-fetoprotein and immunoreactive carcinoembryonic antigen in human hepatocellular carcinoma and hepatoblastoma.

The distribution of alpha-fetoprotein (AFP) and immunoreactive carcinoembryonic antigen (CEA) in 62 hepatocellular carcinomas (HCC) and five hepatoblastomas (HBL) all surgically removed was studied by an immunohistochemical method, and the results were compared with the levels of the antigens in the patients' serum. AFP was present as coarse granules in the cytoplasm of immature tumor cells. AFP-positive tumor cells were detected in 34/43 cases (79.1%) with serum AFP levels higher than 400 ng/ml and in 1/24 (4.2%) of the remaining cases. They were present in 8/32 (25%) cases of relatively well-differentiated HCC (Edmondson's grade I or II), 22/32 (68.8%) of relatively poorly differentiated HCC (Edmondson's grade III or IV), and 5/5 of HBL. An antigen immunoreactive with a conventional rabbit anti-CEA immunoglobulin (DAKO) but not with a murine monoclonal anti-CEA antibody (Hybritech) was present on the surface of bile canaliculi of both non-neoplastic and neoplastic hepatocytes. This CEA cross-reactive differentiation antigen was more often found in relatively well-differentiated tumors, and the presence of this antigen in tumors did not correlate with patients' serum CEA levels. In conclusion, CEA of an oncofetal nature was not produced by either HCC or HBL.