Relationship between the cell-proliferative activity of gastric cancers and that of the normal epithelium.

Samples of gastric carcinomas and of normal gastric mucosa adjacent to tumors from 104 patients with primary mucosal gastric cancer were analysed by flow-cytometry. These patients were divided into two groups according to the histologic type of their tumors (differentiated group and undifferentiated group). The pattern of DNA ploidy and the sizes of the S- and G2M-phase fractions (percentages of cells at each respective phase) were compared between these two groups. DNA aneuploidy was encountered in 25.4% of the cases in the differentiated group and in 21.2% of the cases in the undifferentiated group. The mean sizes of S- and G2M-phase fractions of carcinomas in the differentiated group were 8.85% and 3.75% and they were significantly higher than the mean sizes of S- and G2M-phase fractions of carcinomas in the undifferentiated group (6.97% and 2.92%). Moreover, the S-phase fraction of normal gastric mucosa adjacent to the differentiated adenocarcinoma was 5.75% and this value was significantly higher than that of normal gastric mucosa adjacent to undifferentiated adenocarcinoma (4.80%). These results suggest that the proliferative activity of mucosal gastric cancer cells, as described by flow-cytometry, is higher in cases of differentiated adenocarcinoma than in cases of undifferentiated adenocarcinoma, and that the proliferative activity of normal cells in the gastric mucosa close to where adenocarcinoma develops is higher in cases of differentiated adenocarcinoma than in cases of undifferentiated adenocarcinoma. Thus, differentiated adenocarcinoma seems to develop from gastric mucosa with high proliferative activity.