Study of polymorphisms of UGT1A1 and DPYD genes in chemotherapy for colorectal cancer

Abstract

Background. The personalized approach implies an individual choice of medicines and their doses for the patient, providing the most effective and safe pharmacotherapy. Objective: analysis of the frequencies of UGT1A1 and DPYD polymorphisms and comparison of genotyping data with irinotecan and 5-fluorouracil-induced toxicity, respectively.Materials and Methods. Venous blood of 94 Caucasian patients (46 men and 48 women, median age 61 years). The *6 and *28 UGT1A1 alleles were identified by pyrosequencing, and the *2А DPYD allele was identified by Real-time PCR.Results. The genotyping of 94 patients with colon cancer did not reveal the *2A SNP in the DPYD gene. The frequency rate of the *6 and *28 alleles of the UGT1A1 gene was 0.346 and 0.016, respectively. 24 % of patients receiving chemotherapy with 5-fluorouracil developed side effects associated with the circulatory system and the gastrointestinal tract. Hematological and nonhematological toxic reactions were noted in 48 % and 50 % of patients receiving irinotecan. Severe bilirubinemia was associated with the *28/*28 UGT1A1 genotype. The presence of a high-risk genotype (*28/*1, *28/*28 UGT1A1) correlated with the development of side effects (p=0.040).Conclusion. The absence of carriers of the *2А DPYD allele in the sample with a significant proportion of pronounced adverse toxic reactions to 5-fluorouracil causes the need for the inclusion of new polymorphisms of the DPYD gene in pharmacogenetic testing. The inclusion of genotyping of UGT1A1 polymorphisms into a complex of preliminary examination is advisable when planning treatment with irinotecan.