Histochemical studies on enzyme activities of gastric carcinoma. I. Hydrolytic enzymes.

The activities of five hydrolytic enzymes, alkaline and acid phosphataSe, beta-esterase, leucine aminopeptidase and beta-glucuronidase, of human gastric carcinomas from 180 patients were investigated histochemically. Alkaline phosphatase activity was almost negative in the carcinoma but was weakly positive in this tumor at times (about 10 to 20 per cent). Acid phosphatase activity which displayed a slightly increasing tendency of the reaction in poorly differentiated tumor was variegated and mainly from feeble to moderate in activity. Beta-esterase reaction was in varying degrees with each case, but more malignant the carcinomas, the weaker was the activity. Leucine aminopeptidase was positive in about 30 to 60 per cent of the specimens observed but the reaction was founded to be localized often in some areas and generally similar to alkaline phosphatase reaction. The activities of leucine aminopeptidase, alkaline phosphatase and beta-esterase were positive at a higher rate in mucinous carcinomas than in non-mucin producing one. Beta-glucuronidase activity was slight or moderate in general but rather strong in the early stage of carcinomas.