CDA and gastric cancer: A study conducted by Grau et al. [79] investigated the role of genetic variations in DPYD in place of looking at DPD expression, analyzing the prognostic value of genetic single nucleotide polymorphisms (SNPs) of intratumoral DPYD and CDA (cytidine-deaminase enzyme, which can influence the activity of TS) in patients with GC treated with adjuvant fluoropyrimidine (tegafur).