Expression of blood group A and B antigens in gastric cancer examined by monoclonal antibodies.

Fourty-eight patients with gastric carcinoma were histologically examined and classified according to Laurén as intestinal or diffuse type. Employing monoclonal antibodies, in all samples the expression of blood group A and B antigens was studied using the method of indirect immunoperoxidase reaction. In patients with blood groups A and AB the comparison of expression revealed marked differences between the intestinal and diffuse type carcinomas. In the intestinal type, the expression of the blood group antigens was highly heterogenous, while diffuse type carcinomas displayed a homogenous expression. The obtained differences support Laurén's classification. The staining of supranuclear regions of tumor cells by the monoclonal antibody HE 10 (which reacts with antigenic determinants A and H of type 3 and 4) was found more frequently in intestinal type carcinomas. The possible prognostic significance of these findings is discussed.