Pyloric gland phenotypic expression of gastric cancers developing in the rat fundic glandular stomach.

Mucin histochemistry of experimental gastric cancers induced in rats by N-methyl-N'-nitro-N-nitrosoguanidine or 4-nitroquinoline 1-oxide was analysed by labelled lectin staining for concanavalin A (Con A) after prior periodate oxidation (paradoxical Con A staining) or Arachis hypogarea agglutinin (peanut lectin, PNA) with or without prior periodate oxidation. In the digestive tracts of control-group rats the mucins were classified into class II or III by paradoxical Con A staining. Class II mucins were found in surface mucous cells, goblet cells and the surface coat of intestinal absorptive cells, while class III mucins were present in mucous neck cells, pyloric gland cells and Brunner's gland cells. Although class III mucins showed PNA reactivity, those in pyloric gland cells selectively lost positive staining after 1-4 h oxidation with periodate. Thus phenotypic expression of class III mucin-positive cells in the gastric mucosa could be further classified into mucous-neck-cell type and pyloric-gland-cell type on the basis of this sensitivity to periodate oxidation. Metaplastic cells in fundic mucosa and almost all class III mucin-positive cells in adenomatous hyperplasias, well-differentiated adenocarcinomas and signet-ring cell carcinomas, which developed in both fundic and pyloric mucosae, showed pyloric gland phenotypic expression.