Association of XRCC3 and XRCC4 gene polymorphisms, family history of cancer and tobacco smoking with non-small-cell lung cancer in a Chinese population: a case-control study.

Single-nucleotide polymorphisms (SNPs) of DNA repair genes have been reported to modify cancer risk. This study aimed to determine SNPs of the DNA repair genes X-ray repair cross-complementing group 3 (XRCC3) and X-ray cross-complementing group 4 (XRCC4) and their association with non-small-cell lung cancer (NSCLC) susceptibility in a Chinese population. A total of 507 NSCLC patients and 662 healthy controls were recruited for genotyping. Epidemiological and clinical data were also collected for association studies. The data showed that the rs1799794 G allele in the XRCC3 gene and minor allele carriers of XRCC4, including rs1056503 and rs9293337, were inversely associated with NSCLC risk (GG vs homozygote AA), whereas the rs861537 AG or AA genotype and XRCC4 rs6869366 had a significantly increased NSCLC risk. Furthermore, tobacco smoking over 26 pack-years, a family history of lung cancer, exposure to environmental tobacco smoke (ETS) and negative mental status were risk factors for developing NSCLC. This study suggests that SNPs of XRCC3 and XRCC4 and other environmental factors are risk factors for developing NSCLC in this Chinese Han population.