THE THOMSEN-FRIEDENREICH ANTIGEN-RELATED CARBOHYDRATE ANTIGENS IN HUMAN GASTRIC INTESTINAL METAPLASIA AND CANCER

The Thomsen-Friedenreich antigen (T) is the core disaccharide of O-gly cosylated complex carbohydrates and is presumed to be a cancer-associa ted carbohydrate antigen. However, we recently found that the expressi on of alpha-T and alpha 1-2 fucosyl alpha-T in the gastric surface epi thelia was regulated allogeneically. In the present study we addressed their changes in gastric differentiation disorders. Expression of the T-related antigens was studied histochemically with monoclonal antibo dy MBd and peanut agglutinin in 22 normal, 14 metaplastic, and 54 canc erous tissues. The sialylated antigens were detected after neuraminida se digestion. Gastric mucins were purified and examined to determine w hether they mere the carrier molecules of T. Expression of the normal antigens was decreased or not detected in about 80% of both disorders. Neosialylation of the T-related antigens was observed in the goblet c ells of all metaplastic tissues. The absorptive cells did not express any T-related antigens. In gastric cancers, blocked synthesis, i.e., p recursor accumulation or totally negative expression, was observed in similar to 66% and neosialylation in similar to 40%. The T-related ant igens were carried by mucins. We conclude that blocked synthesis of th e T-related antigens was found in a cancer-specific manner. Neosialyla tion was invariably associated with intestinal metaplasia and occasion ally with cancer.