INVESTIGATION OF POLYMORPHISMS IN GENES XRCC1 AND XRCC3 FOR SUSCEPTIBILITY TO GASTRIC CANCER IN THE NORTHERN REGION OF BRAZIL

Introduction: Gastric cancer is one of the leading causes of cancer death in the world due to its prevalence and bad prognosis. DNA repair system genes are candidates for cancer susceptibility. XRCC (X-ray repair cross-complementing) genes are family members of the DNA repair system, which are polymorphic with several non-synonymous polymorphisms. Several evidences have shown that more than one hundred proteins decoded by the XRCC genes are implicated in four DNA repair pathways, which function as tumor suppressor genes or oncogenes participating in carcinogenesis by regulating post-expression of homologous target genes. Polymorphisms in these genes can help clarify gastric tumor progression. Objectives Investigate genetic polymorphisms in XRCC1 (rs1799782) and XRCC3 (rs861539) genes and its possible association with the susceptibility to gastric cancer in patients of a population of the Northern region of Brazil. Methodology Were included 95 individuals with gastric adenocarcinoma in the case group and 94 cancer-free individuals in the control group. The QuantStudio 12K Flex Real-Time PCR System (Applied Biosystems®, USA) was used to genotyping the two polymorphisms. The statistical analyses were carried out using statistical program SPSS v. 20.0 (SPSS, Chicago, IL, USA). Results No significant results were found about association between XRCC1 (rs1799782) polymorphism and gastric cancer. However, , the polymorphisms of the XRCC3 gene (rs861539) demonstrate an association of susceptibility to gastric cancer. Individuals with the mutant allele T presented eighteen(18x) more risk to develop gastric cancer in comparison to individual that are CC homozygous (p -value = 3.81E-7; OR = 18.873, IC 95% = 6.073-58.651). Conclusion The study suggests that the rs861539 polymorphism of the XRCC3 gene may be related to gastric cancer susceptibility in individuals in Northern Brazil.