1984 Volume 75 Issue 6 Pages 540-547
The distribution of blood group ABH antigens, their precursor I(Ma) antigen, Lewisa antigen and monoclonal antibody-defined tumor-associated antigen CA 19-9 in gastric cancers and their surrounding non-neoplastic mucosa was studied by using immunohistochemical methods. ABH antigens were localized in the foveolar epithelium except for a few cases presumed to be non-secretors, but ABH antigens were lost focally from metaplastic mucosa. In contrast, Lewisa and I(Ma) antigens were present in the foveolar epithelium of non-secretors and metaplastic mucosa where ABH antigens were not detected. Gastric cancers also showed focal loss of ABH antigens and gain of Lewisa and I(Ma) antigens, and the cancer cells showed marked heterogeneity in antigen expression compared with non-neoplastic mucosa. Expression of incompatible blood group antigen (A-like antigen) reactive with monoclonal anti-A antibody was also detected in cancer cells of blood group O and B cases. CA 19-9 (sialylated-Lewisa) was detected in 62% of gastric cancers and in the restricted areas of gastric mucosa where Lewisa was positive.