Intestinal Phenotypes of Stomach Cancers Arising after Helicobacter pylori Eradication in Carcinogen-treated Mongolian Gerbils

Aims: We have previously demonstrated the importance of gastric and intestinal phenotypic expression forthe histogenesis of stomach cancer. However, the phenotypes of stomach cancers arising after Helicobacterpylori (Hp) eradication have hitherto remained unclear. We therefore examined a series of lesions occurringafter Hp eradication in the Mongolian gerbil (MG) model.
Methods: Totals of 6 and 20 advanced glandularstomach cancers were evaluated in Hp–eradicated and Hp–infected MGs treated with N-methyl-N-nitrosourea(MNU-MGs), using several gastrointestinal epithelial phenotypic markers. The lesions were dividedphenotypically into gastric (G type), gastric-and-intestinal mixed (GI type), intestinal (I type), and null (N type)phenotypes.
Results: All 4 differentiated type lesions in Hp-eradicated MNU-MGs were classified as G type,while both of the undifferentiated lesions exhibit the GI type. In Hp-infected MNU-MGs, the lesions wereclassified as 10 G, 8 GI, and 2 I types, with undifferentiated type lesions having more intestinal phenotypicexpression than their differentiated counterparts (P < 0.01).
Conclusions: Our data suggest that the differentiatedstomach cancers exhibit the G type in Hp-eradicated MNU-MGs, suggesting that a kind of non-neoplastic Gtype gland may be precancerous. Intestinalization may still occur, especially in undifferentiated stomach cancers,even if Hp eradication is successful.