also show that hypermethylation patterns of GSTP1, APC, RASSF1A, PTGS2, and MDR1 is able to be used to distinguish primary prostate cancer from benign prostate tissues, hypermethylation of CpG island at EDNRB is correlated with tumor grade and stage of primary prostate cancers, and hypermethylation of CpG island of PTGS2 is associated with increased risk of recurrence (135). This evidence concerns the gene GSTP1 and prostate cancer.