TYMS and colorectal carcinoma: In particular, human CRC cell lines Lovo 92 and WiDr T and their transfected variants were exposed to novel antifolate TS inhibitors and 5-FU, whose active metabolite 5-fluoro-2′-deoxyuridine-5′-monophosphate (FdUMP) competes with dUMP, and forms a ternary complex with 5,10-methylene-tetrahydrofolate and TS.