V89L Polymorphism of the 5α-Reductase Type II Gene (SRD5A2), Endogenous Sex Hormones, and Prostate Cancer Risk

Abstract

We examined the combined effect of circulating sex hormones and SRD5A2 V89L polymorphism on prostate cancer risk in a case-control study (300 cases and 300 controls) nested within the Carotene and Retinol Efficacy Trial. A moderate increase in risk associated with above-median serum levels of androstenedione and dehydroepiandrosterone sulfate (DHEAS) was present irrespective of V89L genotype. However, in L/L or V/L men, above-median DHEAS levels were associated with an increased risk of aggressive tumors [odds ratios (OR), 3.12; 95% confidence interval (95% CI), 1.28-7.63] but not of nonaggressive ones (OR, 0.56; 95% CI, 0.25-1.25). Above-median serum levels of free estradiol were associated with a lower risk, especially for aggressive cancer. The association with aggressive disease was more pronounced in men with a V/V genotype (OR, 0.34; 95% CI, 0.14-0.81), than in men with an L/L or V/L genotype (OR, 0.77; 95% CI, 0.37-1.60). Above-median levels of 3alpha-diol G were associated with an increased risk, but only in men with the L/L or V/L genotype (OR, 2.16; 95% CI, 1.31-3.56). The increase in risk in L/L and V/L men was restricted to aggressive tumors. Our study observed that only in men with the L/L or V/L genotype were increased serum levels of DHEAS and 3alpha-diol G positively associated with a higher risk of aggressive prostate cancer. Free estradiol levels were negatively associated with risk of aggressive prostate cancer in men with the V/V genotype. However, the absence of an overall association between V89L genotype and aggressive prostate cancer argues for a cautious interpretation of these observations.