Association of Arg194Trp and Arg399Gln Polymorphisms of XRCC1 Gene and Risk of Differentiated Thyroid Carcinoma in IranianAzeri Patients

Background: The thyroid cancer (TC) is one of endocrine malignancies which contributes to more than 50% of all deaths from endocrine cancers. Gene polymorphisms including DNA repair genes such as XRCC1 (X-ray repair cross-complementing group 1) gene are thought to modify DNA repair capacity and relate to cancer risk. Objectives: The aim of the study was to detect the association between XRCC1 polymorphisms and increased risk of thyroid carcinoma among Iranian-Azeri patients. Methods: This case-control study was performed on 114 differentiated thyroid carcinoma patients and 91 normal control subjects. Single nucleotide polymorphisms (SNPs) of 194 C T and 399 G A of XRCC1 gene were genotyped by polymerase chain reactionrestriction fragment length polymorphism (PCR-RFLP). Results: In the present study, polymorphism at codon 194 of the XRCC1 gene was not found in case and control groups (P = NC (not calculated). All of the case and control subjects were 194C/C. Unlike 399 G A genotype (P 0.001, OR = 0.184, CI = 0.09 - 0.372), there was a positive association for 399G/G (P 0.001, OR = 3.304, CI = 1.624 - 6.780) and 399 A/A (P 0.001, OR = 14.143, CI = 1.861 - 296.277) genotypes with differentiated thyroid carcinoma. The frequency of variant 399 A allele among the cases was slightly higher than that in controls (P = 0.269, OR = 0.798, CI = 0.535 - 1.190). Conclusions: Based on these results, the XRCC1 399G A genotype could be used as a useful molecular biomarker to predict genetic susceptibility for differentiated thyroid carcinoma in Iranian-Azeri patients.