Volume 9, Number 3Review ArticlesTwenty Years of PSA: From Prostate Antigen to Tumor MarkerDiagnostic UpdateGabriela De AngelisStephen D MikolajczykHarry G RittenhouseAxel SemjonowL Blair ShamelThe measurement of prostate-specific antigen in serum is credited with dramatic advances in the early detection of men with prostatic carcinoma. This report summarizes the history of biochemical research and the current understanding and application of prostate-specific antigen in prostate cancer diagnostics. [Rev Urol. 2007;9(3):113-123]Prostate cancerProstate-specific antigenHuman kallikrein