Association between expression of sialosyl-Tn antigen and intestinalization of gastric carcinomas.

We examined immunohistochemically the expression of sialosyl-Tn antigen (STN) in 137 primary gastric carcinomas. In the non-neoplastic mucosa, STN was expressed in all goblet cells, most absorptive cells and Paneth cells of intestinalized tubules, whereas it was not seen in the gastric mucosa proper. We evaluated the association between the mucin-histochemical findings of intramucosal carcinomas and the STN-expression. STN was expressed in 8 of 20 undifferentiated-type carcinomas, all of which were mucin-histochemically of the gastric type. STN was expressed in 25 of 51 differentiated-type carcinomas, among which it was expressed in 3 of 12 gastric-type, 11 of 17 intestinal-type and 11 of 22 mixed-type adenocarcinomas. The extent of STN expression in the intestinal-type adenocarcinomas was significantly higher than in gastric-type adenocarcinomas and undifferentiated-type carcinomas, and that seen in mixed-type adenocarcinomas was significantly higher than in the gastric-type adenocarcinomas. We also examined STN expression in early and advanced carcinomas. As the depth of carcinoma invasion progressed, the extent of STN expression was significantly higher and its incidence was significantly higher. Our findings suggest that STN expression reflects intestinalization of the gastric mucosa, and that a kind of intestinal metaplasia occurs in progressing gastric carcinoma cells.