[Thymidylate synthase inhibition in malignant tumors after oral administration of UFT].

Surgical resection of solid tumors was undertaken five to six hours after the oral administration of UFT (300-500 mg/body) in five patients, who were (then) assayed for 5-fluorodeoxyuridylate (FdUMP), total dTMP synthase (TS) and non-FdUMP-bound, free enzyme. Three patients had gastric cancer, and two had mammary cancer. Control solid tumors were obtained without, the drug in eight patients.