KLK3 and prostate cancer: Prostate carcinoma is a common disease that occurs in men over 50 years old; serum prostate-specific antigen (PSA), which is produced by all types of prostate tissue, is one of the most important biomarkers for detecting prostate cancer, guiding decisions about biopsies of the prostate and offering a way to monitor disease progression.[1,2] Total PSA (tPSA) includes unbound and bound (or complexed) PSA forms; it refers to the sum of all immunologically detectable forms of serum PSA.