Identification of an SCLC susceptibility rs7963551 genetic polymorphism in a previously GWAS-identified 12p13.33 RAD52 lung cancer risk locus in the Chinese population.

As a well-known DNA repair gene, RAD52 plays an essential role in homologous recombination repair of double strand break, maintenance of genomic stability and prevention of cell malignant transformation. Previous genome-wide association studies (GWASs) have identified common genetic variants at 12p13.33 RAD52 locus associated with lung cancer risk in Caucasians. However, little or nothing has been known about the RAD52 single nucleotide polymorphisms (SNPs) in small cell lung cancer (SCLC) in the Chinese population. As a result, we examined the association between six RAD52 SNPs (rs10849605, rs1051669, rs10774474, rs11571378, rs7963551 and rs6489769) and SCLC susceptibility in Chinese. After 520 SCLC cases and 1040 controls in two independent case-control sets were genotyped, odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by logistic regression. We found that only the RAD52 rs7963551 SNP was significantly associated with SCLC risk among six RAD52 SNPs genotyped. The odds of having the rs7963551 CA genotype in SCLC patients was 0.38 (95% CI = 0.24-0.62, P = 1.1×10(-4)) compared with the CC genotype. Stratified analyses of association between rs7963551 SNP and SCLC risk indicated that the functional polymorphism was only significantly associated with decreased risk among smokers but not nonsmokers. Our results demonstrated that the functional RAD52 rs7963551 SNP contributes to susceptibility to developing SCLC in the Chinese population.