Study of Polymorphism Pro198Leu of GPX-1 gene as a risk factor in patients with colorectal cancer

Background: Oxidative stress is a condition in which the balance is disrupted between reactive oxygen species (ROS) and antioxidant. Glutathione peroxidase 1(GPX-1), as one of the antioxidant enzyme remove the ROS in a continuous process. One of the functional polymorphism of GPX1 gene is Pro198Leu polymorphism. The aim of this study was to study the association between GPX-1 Pro198Leu polymorphism with the risk of colorectal cancer. Materials & Methods: in this case-control study, 130 patients with colorectal cancer were compared with 170 healthy subjects. Genomic DNA was extracted from peripheral blood leukocytes. Determination of DNA genotyping in GPX-1 Pro198Leu polymorphism were performed by the polymerase chain reactionrestriction fragment length polymorphism (PCR-RFLP). The χ 2 -test was used for statistical analyses. Results: The GPX1 genotype frequencies were 64% for CC, 24% for CT and 12% for TT in control group, and 60% for CC, 30% for CT and 12% for TT among the patients. The C allele frequency in cases and controls including 0.75 and 0.76 and T allele frequency was including 0.25 and 0.24. Based on these data, there was no significant differences in the GPX1 Pro198Leu genotypes and allele frequencies between cases and controls (P=0.2). Conclusion: The result of this study suggested that GPX-1 Pro198Leu polymorphism could not be a risk factor for colorectal cancer. However, studies in larger populations are needed in order to confirm the results.