[An immunohistochemical study on primary carcinoma of the liver]

Using 109 hepatocellular carcinomas (HCG), 34 cholangiocellular carcinomas (CCC), 4 mixed hepatocellular-cholangiocellular carcinomas (MHC) and 24 metastatic adenocarcinomas in the liver (MA), an immunohistochemical study on primary carcinoma of the liver was performed by means of the ABC method for carcinoembryonic antigen (CEA), epithelial membrane antigen (EMA), tissue polypeptide antigen (TPA) and keratin. The material consisted of surgical specimens of Kosin Medical College including 50 HCC, 17 CCC and 1 MHC, surgical specimens of 20 HCC from the University of Occupational and Environmental Health, Japan (UOEH) and autopsied specimens from UOEH that included 39 HCC, 17 CCC, 3 MHC and 24 MA. All the specimens were fixed with 10-15% formalin and embedded in paraplast manually at Kosin Medical College and by utilizing an automatic embedding machine with a decompressing procedure at UOEH. The antigenicity of TPA and keratin was preserved better in the specimens of Kosin Medical College than in those from UOEH. It is therefore assumed that manually embedded specimens are superior to specimens embedded by using an embedding machine with regard to the preservation of some antigenicities. The immunoreactivity of the 4 antigens in CCC cells was significantly higher than that in HCC cells, and the intracellular localization of antigens generally showed several characteristics in HCC and CCC. However, as the same localization of antigens is also seen in both HCC cells and CCC cells, it is considered that the immunohistochemical examination using plural antibodies is not always useful for a differential diagnosis between HCC and CCC, which is difficult in conventional sections. That TPA in HCC may be an oncodevelopmental antigen is suggested by the facts that the higher the grade of HCC, the higher the immunoreactivity of HCC cells, that hepatocytes with possible higher activity sometimes showed a positive reaction in the present study and that TPA is expressed in fetal hepatocytes in a fetus up to 20 weeks in the literature.