XRCC2 and neoplasm: After a multivariate adjustment for age, sex, smoking status, tumor histology, KPS, tumor stage, application of chemotherapy, and radiation dose, the HRs were statistically significant in both RAD51 −135G>C and XRCC2 R188H SNPs (CG/CC vs. GG: adjusted HR = 1.70; 95% CI, 1.14–2.62, P = 0.009; and AG vs. GG: adjusted HR = 1.70; 95% CI, 1.02–2.85, P = 0.043, respectively) (Table 2 and Fig. 1A, 1B).