0 By Editor1 In Botanical Medicine, Fertility, Men's Health, Nature Cure, OncologyPosted September 22, 2007PSA: A Failed Screening TestEric Yarnell, ND Prostate-specific antigen (PSA) is a protease produced by prostate cells to liquefy the semen. Though it is found in non-prostatic cells in minute amounts, it is largely […] READ MORE