Prevalence of prostate cancer: GTCs: 90% chemoprevention efficacy in men subjected to high risk for developing CaP (p < 0.01); Total serum PSA values: GTCs: lower, at any time point, compared to control; Changes in LUTS as assessed by IPSS and QoL scores: GTCs: decrease for 3 months, compared with control (p < 0.05)). This evidence concerns the gene KLK3 and Familial prostate cancer.