The gastric- and intestinal-type properties of 15 human gastric cancers, which were transplanted into nude mice, were studied biochemically and histologically. Enzyme activities were determined in the crude extracts of cancer tissues: pepsinogen isozymes as gastric marker enzymes; and sucrase, aminopeptidase (microsomal), and alkaline phosphatase as intestinal marker enzymes. By hematoxylin and eosin staining and paradoxical concanavalin A staining, gastric cancer tissues were classified into gastric type (pyloric gland cell type and surface mucous cell type) and intestinal type (goblet cell type and intestinal absorptive cell type). On the basis of their properties, human gastric cancers were classified into four types: (a) intestinal type; (b) gastric type; (c) intestinal plus gastric type; and (d) unclassified type, showing no gastric- or intestinal-type properties.
Of six well-differentiated adenocarcinomas, four were of intestinal type, one of gastric type, and one of intestinal plus gastric type. All of the intestinal-type carcinomas showed sucrase activity. Of the three signet ring cell carcinomas, one was classified as a gastric type, one as an intestinal plus gastric type, and one as an unclassified type. Of the six poorly differentiated adenocarcinomas, five were of the intestinal type and one of the unclassified type.
The present results clearly showed the appearance of intestinal-type properties in gastric cancer cells not only in so-called intestinal-type carcinomas, but also in diffuse-type carcinomas.
This work was supported in part by grants-in-aid for cancer research from the Ministry of Education, Science, and Culture of Japan.