In this study, we aimed to assess the relationship between PCa and polymorphisms in the genes encoding endothelial nitric oxide synthase (eNOS), catalase (CAT), and myeloperoxidase (MPO).
Among current smokers with low serum α-tocopherol concentrations, MPO G/A+A/A, the genotypes downregulating oxidative stress, were associated with an increased risk for aggressive prostate cancer (OR = 2.06, 95% CI = 1.22-3.46).
Among men carrying the variant allele for thioredoxin reductase 2 (TXNRD2) rs4485648, microsomal epoxide hydrolase 1 (EPHX1) rs17309872, or myeloperoxidase (MPO) rs11079344, an increased prostate cancer risk was observed with high, compared with no, petroleum oil/petroleum distillate (OR=1.9, 95% CI: 1.1-3.2, P interaction=0.01; OR=2.1, 95% CI: 1.1-4.0, P interaction=0.01), or terbufos (OR=3.0, 95% CI: 1.5-6.0, P interaction=2.0×10(-3)) use, respectively.
Associations between MPO -463 G to A genotype (rs2333227) and prostate cancer risk were only noted among men with aggressive cancer, with more than a 2-fold risk reduction among men with AA genotypes (OR = 0.4, 95% CI = 0.2-1.0); MnSOD was not associated with risk overall, but the MnSOD T to C (Val-9Ala, rs4880) polymorphism modified associations between risk of clinically aggressive prostate cancer and dietary iron intake (P for interaction = 0.02).