Chemotherapeutic agents used in the treatment of colorectal cancer include capecitabine, a prodrug of fluorouracil and a thymidylate synthase inhibitor; oxaliplatin, an alkylating and cross-linking agent; fluorouracil, an antimetabolite analogue of pyrimidine and a thymidylate synthase inhibitor; and irinotecan, which effectively acts on the S phase of the cell cycle and causes double-stranded DNA breaks. Here, TYMS is linked to colorectal cancer.