Secreted by the prostatic epithelium, PSA is organ-specific, not cancer-specific, which means that other pathologies also influence PSA levels, such as prostatitis or benign prostatic hyperplasia (BPH), androgen levels, DRE, body mass index (BMI) (hemodilution of PSA), prostatic trauma (biopsy), urinary retention, ejaculation under 24 h [7]. Here, KLK3 is linked to cancer.