Apomucin expression and association with Lewis antigens during gastric development

In normal stomach, MUC5AC and MUC6 apomucins are associated with Lewis type s 1 and 2, respectively, and this association is lost during gastric carcin ogenesi The expression of gastric (MUCAC, MUC6) and intestinal (MUC2, MUC4) apomucins and Lewis antigens during gastric development, using single and double labeling immunohistochemistry on fetal tissues (15-41 weeks), was an alyzed and related to the tumor expression patterns. Apomucin expression in other fetal tissues was also analyzed. In gastric samples, MUC2 is detecte d in 14 of 19 showing no correlation with fetal age, and MUC4 is not detect ed. MUC5AC and MUC6 are always highly detected and are coexpressed and asso ciated with both types of Lewis antigens. These patterns change progressive ly with the development of the adult gastric morphology. MUC2 is detected i n the small intestine, colon, and pancreas, MUC4 is expressed in the colon; MUC5AC is detected in the small intestine, and MUC6 is found in the duoden um and pancreas. The patterns of apomucin expression and association with L ewis antigens during development are complex, but then is a trend toward th e establishment of the adult pattern, with the exception of MUC4, which is not detected. These patterns found in fetal stomach indicate that alteratio ns reported in gastric tumors do not fully recapitulate a developmental phe notype.