Early detection of human gastric cancer based on morphologic and enzymologic studies.

Atypical glandular proliferations of gastric mucosa and carcinomas were studied with histologic, cytophotometric, and enzymologic methods in 35 resected human stomachs. By the use of Feulgenis cytophotometry and a new mathematical test developed by us, aneuploid DNA content could be demonstrated in some grade II and grade III dysplasias as well as carcinomas. Alkaline phosphatase isoenzymes were detected with polyacrylamide disk gelelectrophoresis. Liver-type isoenzymes were detectable, though with varying rates, in both intact gastric mucosa and in lesions studied. The intestinal-type isoenzyme, however, did not occur in intact gastric mucosa or in inflammatory epithelial changes, in contrast to all cases of intestinal metaplasia and some of the gastric dysplasias and carcinomas, where it was present. Placental-type ALP isoenzyme (Regan enzyme) was observed only in grade II and grade III dysplasias and carcinomas. Simultaneous occurrence of Regan isoenzyme and aneuploid DNA content could be observed in 70% of dysplasias and carcinomas. In view of our observations, one can suppose that the presence of these markers in dysplasia is suggestive of malignant transformation.