XRCC1 and nasopharyngeal carcinoma: For the XRCC1 Arg194Trp polymorphism, individuals with the XRCC1 Trp194Trp genotype had a nearly 0.50-fold decreased risk of developing NPC compared to those with the Arg194Arg genotype (OR = 0.48; 95% CI, 0.27–0.86, P = 0.01); the risk for developing NPC for individuals with the Arg/Trp genotype did not appear to differ significantly (OR = 0.79; 95% CI, 0.60–1.05).