[Biochemical criteria of 5-fluorouracil sensitivity and resistance of stomach tumors].

It has been shown that based on the intensity of labeled 5-fluorouracil incorporation in RNA and activity of uridinekinase and thymidinekinase or alkaline phosphatase activity in tumorous tissue of the stomach one can form the judgement about the sensitivity of gastric carcinomas to chemotherapy with 5-fluorouracil.

[Biochemical differences in the tumor cells of 5-fluorouracil-sensitive and -resistant strains of Ehrlich ascitic carcinoma].

Essential differences have been disclosed as regards 5-FU-6-3H incorporation into RNA of tumor cells of Ehrlich's ascites carcinoma strains susceptible and resistant to 5-FU in vitro. In vivo the rate of drug incorporation into RNA of tumor cells was fairly high and noticeably varied depending on tumor cell susceptibility to 5-FU. At the same time the rate of drug incorporation into RNA of liver, spleen, kidney, and intestinal mucosa cells was negligible, thus attesting to a selective action of 5-FU on tumor cells.