The results from the meta-analysis indicated no statistically significant association between XRCC1 Arg399Gln polymorphism and tumor response under all the genetic models (figure 2) (A vs. G: OR = 1.17, 95% CI 0.94–1.46; dominant model: OR = 1.30, 95% CI 0.99–1.71; recessive model: OR = 1.19, 95% CI 0.74–1.90; (Table 5), and no single study altered the result substantially by the sensitivity test. This evidence concerns the gene XRCC1 and neoplasm.