GSTP1 and prostate intraepithelial neoplasia: Hypermethylation of a CpG island in the promoter of GSTP1, which encodes a detoxification enzyme, π-class glutathione S-transferase, is a molecular hallmark of PCa; it is present in ~70% of high-grade prostatic intraepithelial neoplasia (HG-PIN) lesions and in more than 90% of adenocarcinomas [3,9].