Investigation of Thymidylate Synthase Induction in Colorectal Tissues after Administration of Anticancer Drug, Fluorinated Pyrimidine Fluoride Derivatives

Abstract

Patients with colorectal carcinoma were treated with UFT and Tegafur for 7 days repeated (600mg per day), and 5-FU concentrations in tissues and inhibition rate of Thymidylate Synthase (TS) were compared. As a control, total amounts of TS were determined in tissues from patients who did not receive any drug. Total amounts of TS were compared between UFT or Tegafur group and control group.
Both 5-FU concentration and inhibition rate of TS in tumor tissues were significantly higher in UFT group than Tegafur group.
Total amounts of TS in tumor tissues, normal mucous membranes, and lymph nodes were significantly higher in patients treated with drugs than patients who did not receive any drug. Particularly, high level of TS was induced in patients treated with UFT. Relationship between total TS in tumor tissues and inhibition rate of TS were then studied. Inhibition rate of TS remained 50 to 60% regardless of total TS.