For example, Li et al. [76] reported that among men with the AA genotype of codon 16 (rs4880) of SOD2, a gene that encodes the mitochondrial antioxidant enzyme manganese superoxide dismutase, men with higher selenium levels had lower risk of total prostate cancer (RR: 0.3, 95% CI: 0.2–0.7) and of clinically aggressive prostate cancer (RR: 0.2, 95% CI: 0.1–0.5) compared to those with lower selenium levels. This evidence concerns the gene SOD2 and Familial prostate cancer.