Frequency of c.1905+1G>A Mutation in DPD Gene among Patients with Colorectal Cancer in Mazandaran Province

5-Flourouracil (5-FU) is one of the most common chemical drugs used in chemotherapy of patients with cancers. Dihydropyrimidine dehydrogenase (DPD) is a critical enzyme in the catabolism of 5-FU. More than 80% of the administered 5-FU is catabolized by DPD. c.1905+1G>A mutation on DPD gene is the most important mutation associated with DPD enzymatic deficiency which leads to toxicity. The aim of this study was to investigate the frequency of c.1905+1G>A mutation on DPD gene among patients with colorectal cancer in Mazandaran province, north of Iran, 2016. In this descriptive study, 60 patients with colorectal cancer were selected and the genomic DNA was extracted from 200 µl of peripheral blood using commercial DNA extraction kit (Yekta Tajhiz Iran). For identification of c.1905+1G>A mutation on DPYD gene PCR-RFLP method was used applying Mae II restriction enzyme. The patients were 26 females and 34 males. The c.1905+1G>A mutation was detected only in one male subject (1.6%) in the heterozygous state. The present study showed low frequency of c.1905+1G>A mutation in Mazandaran province. However, genetic test is recommended for identification of this mutation in oredr to predict the toxicity of the 5-FU in patients with colorectal cancer.