UFT: Mechanism of drug action

The mechanism of action of fluorouracil (5-FU) and the oral fluoropyrimidin es and the importance of biochemical modulation and inhibition of dihydropy rimidine dehydrogenase for oral application of the prodrugs of 5-FU are dis cussed. The regulation of thymidylate synthase, as well as its roles as a t arget for antineoplastic activity and in drug resistance, are also mentione d. The more downstream events of 5-FU action and their implication in 5-FU resistance, whit the possible involvement of the Fas/FasL system and the pr oteins associated with apoptosis regulation, are highlighted. Also discusse d is the suggestion that the oral 5-FU prodrug tegafur and uracil (UFT) and its metabolites function as an angiogenesis inhibitor.