Overall, there was little evidence to suggest an interaction between genotypes and BMI, except that obese men (BMI≥30 kg/m2) with heterozygote G/A genotype in ESR2 38 bp 3′ of STP G>A had a 72% lower risk of prostate cancer (P = 0.026), and that more A alleles in ESR2 5659 bp 3′ of STP G>A were associated with increased prostate cancer risk in men with BMI <25 kg/m2 (p-value for trend = 0.053). This evidence concerns the gene ESR2 and prostate cancer.