In case of 5-FU, dysregulation of uridine monophosphate synthetase (UMPS), an essential enzyme for uridine biosynthesis and conversion of 5-FU, has been linked with reduced expression of the Bcl2 like ovarian killer (BOK) protein in CRC cells, which are resistant to 5-FU treatment [12]. This evidence concerns the gene UMPS and colorectal carcinoma.