TYMS and cancer: TYMS, a key enzyme participated in the DNA biosynthesis, catalyzes the conversion of dUMP to dTMP to provide the only de novo synthesis of thymidine.[34] It has been proved that TYMS regulates the expression of some crucial cancer genes as an RNA-binding protein via translational repression.[35–37] Therefore, alteration in TYMS activity is thought to be connected with tumorigenesis through disruption of genome integrity, imbalance in repair mechanisms, changes of methylation status, and cell cycle dysregulation.