GSTP1 and cancer: Indeed, a commercial test (ConfirmMDx for Prostate Cancer, MDx Health), based on APC (Adenomatous Polyposis Coli), GSTP1, and RASSF1 (Ras Association (RalGDS/AF-6) Domain Family Member 1) hypermethylation in cancer-negative biopsies, offers a negative predictive value of 90%39.