The key enzymes, such as thymidylate synthase (TS), thymidine phosphorylase (TP), orotate phosphoribosyltransferase (OPRT), and dihydropyrimidine dehydrogenase (DPD) were used as predictive biomarkers of the efficacy of 5-FU chemotherapy and targeted therapy in CRC cells [9]. The gene discussed is TYMS; the disease is colorectal carcinoma.