Circulating blood group-related antigen(s) in cancer patients detected by the monoclonal antibodies produced against hepatocellular carcinoma cell line.

Two murine monoclonal antibodies (MAbs) S1 and S3 produced against a human hepatoma cell line were found to recognize both H (type II) antigen and difucosyl type II structure (Y-antigen). Both MAbs reacted with hepatoma tissues obtained from surgical resection. A double determinant enzyme immunoassay (DDEI) employing these MAbs successfully detected the corresponding antigen(s) in the supernatant which is either released or shed from the immunizing hepatoma cell line. DDEI also revealed that these antibodies reacted with the corresponding antigen(s) in the sera from cancer patients. Among the sera from O blood group donors, individuals with primary hepatoma showed markedly higher levels of antigen concentration than the normal control group. Several cases with gall bladder, lung and pancreas carcinomas, which are of O blood type, also had significantly higher levels of antigen. One case with ovarian cancer of B blood type showed higher antigen concentration than normal O blood group donors suggesting a change in the carbohydrate structure of the corresponding antigen(s) in the serum. These data suggest that the release or the shedding of the antigen(s) from the cells may increase due to the malignant transformation, resulting in higher amounts of the antigen(s) in the serum of certain cancer patients.