Ever since 1941, when it was discovered that lowering testosterone levels via orchiectomy or estrogen injections improved symptoms in patients with metastatic, exogenous hormone naïve disease, androgen deprivation therapy (ADT) became the mainstay treatment for locally advanced prostate cancer (clinical tumor stages T3–T4, PSA > 20 ng/mL) [2]. This evidence concerns the gene KLK3 and prostate cancer.