TS (TYMS)

TS, or thymidylate synthase (TYMS), is an enzyme that generates thymidine monophosphate (dTMP) which becomes phosphorylated to generate thymidine triphosphate (dTTP) for use in DNA synthesis and repair. The reactions catalyzed by TS also yield dihydrofolate as a secondary product. As an anti-cancer chemotherapy target, thymidylate synthase can be inhibited by fluoropyrimidine or certain folate analogues. High TS has been associated with lack of response to fluoropyrimidine, whereas low or no TS expression has been associated with improved clinical response to fluoropyrimidine.