The group of benign prostate disease seemed adequate for several order of reasons: 1) the diagnosis was contemporary with that of cancers; 2) their advanced age at diagnosis allowed matching with elderly prostate cancer patients; 3) all patients underwent digital rectal examination, PSA testing and prostate needle biopsy, making the possibility of crossover remote, and 4) most men develop nodular prostate hyperplasia or chronic prostatitis by the 7th–8th decades of life, making it normal in men of that age to carry benign prostatic disease. Here, KLK3 is linked to prostate cancer.