Regarding the Met1097Val polymorphism, no significant association with bladder cancer risk was found in any of the genetic models evaluated (Val vs. Met: OR = 1.10, 95% CI, 0.97-1.25; Val/Val vs. Met/Met: OR = 1.23, 95% CI, 0.86-1.75; Val/Val + Val/Met vs. Met/Met: OR = 1.12, 95% CI, 0.96-1.30; Val/Val vs. Met/Met + Val/Met: OR = 0.81, 95% CI, 0.57-1.14).
In classification and regression tree analysis, we observed gene-gene interactions among CCNH V270A, ERCC6 M1097V and RAD23B A249V in ever smokers: smokers with the variant alleles at these three loci had an almost 30-fold increased risk of bladder cancer [odds ratio (OR): 29.6, 95% confidence interval (CI): 9.3-93.7].