Aim: To investigate the association of DPYD, MTHFR and TYMS polymorphisms on 5-fluorouracil (5-FU) related toxicities and patient survival. Materials & methods: A total of 103 colorectal cancer patients prescribed 5-FU were included in the study. Genotyping was conducted for several DPYD, MTHFR and TYMS polymorphisms using a microarray analyzer. Results: DPYD 496A>G polymorphism was found to be significantly associated with 5-FU related grade 0-2, but not severe toxicities (p = 0.02). Furthermore, patients with DPYD 85TC and CC genotypes had longer progression and overall survival times compared to TT genotypes in our study group (log rank = 6.60; p = 0.01 and log rank = 4.40; p = 0.04, respectively). Conclusion: According to our results, DPYD 496AG and GG genotypes might be protective against severe adverse events compared to the AA genotype. Another DPYD polymorphism, 85T>C, may be useful in colorectal cancer prognosis. Further studies for both polymorphisms should be conducted in larger populations to achieve accurate results.
Keywords: DPYD; MTHFR; TYMS; adverse effects; colorectal cancer; fluoropyrimidines; pharmacogenetics; polymorphisms.
5-fluorouracil (5-FU) is a widely used drug for chemotherapy in colorectal cancer. In this study, we investigated the relationship between the severity of 5-FU induced adverse events and several variations in DPYD, MTHFR and TYMS genes, which encode the enzymes involved in 5-FU metabolism in a total of 103 colorectal patients. We also examined the relationship between the polymorphisms and progression-free and overall survival times of the patients in our study group. Among the variations, DPDY 496A>G polymorphism was found to be associated with 5-FU induced adverse events. Also, the DPYD 85T>C polymorphism was detected to be associated with longer progression-free and overall survival times.