Objective:MnSOD plays a vital role in carcinogenesis,partly in that it converts superoxide radical to oxygen and hydrogen peroxide.The conflicting results of studies on the role of MnSOD polymorphism(Val-9Ala) with the risk of prostate cancer encouraged us to perform a meta-analysis to examine the association.Methods:A comprehensive search was conducted to examine all the eligible studies of MnSOD polymorphism and prostate cancer risk.We used odds ratios(ORs) with 95% confidence intervals(CIs) to assess the strength of the association.The pooled estimates of ORs were computed using the fixed-effects model or random-effects model.Results:Ten eligible studies,including 4 608 cases and 5 861 controls,were included in this meta-analysis.Overall,individuals with Ala/Ala and Ala/Val genotypes have an increased risk of prostate cancer,compared with those carrying the Val/Val genotype(Ala/Ala vs.Val/Val:OR=1.13;95% CI=1.02～1.25;P = 0.020,Pheterogeneity=0.370;Ala/Val vs.Val/Val:OR=1.14;95% CI=1.04～1.25;P = 0.004,Pheterogeneity=0.940).This significant association was also found in a dominant model with-9Ala allele(Ala/Ala+Ala/Val vs.Val/Val:OR=1.12;95% CI:1.03～1.22;P = 0.009,Pheterogeneity=0.64).In the subgroup by ethnicity,it was observed that significantly elevated prostate cancer risk was associated with-9Ala allele in Caucasians(Ala/Ala vs.Val/Val:OR=1.14;95% CI=1.03～1.27;P = 0.01,Pheterogeneity=0.31;Ala/Val vs.Val/Val:OR=1.14;95% CI=1.04～1.24;P = 0.006,Pheterogeneity=0.87) but not in African-Americans.Furthermore,this meta-analysis showed that the-9Ala allele was associated with both nonaggressive and aggressive prostate cancer risks.Conclusion:Our meta-analysis suggests that MnSOD Val-9Ala polymorphism is associated with prostate cancer risk,especially in Caucasians.
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