GSTP1 and prostatitis: As an example, the frequency of methylation at the promoter region of Glutathion S-transferase Pi 1 (GSTP1), a gene involved in DNA repair, was found elevated not only in more than 90% of PCa cases, but also in over 50% of PCa precursor lesions, confirming that this is an early event in prostate carcinogenesis [42,43,44].