GSTP1 and neoplasm: Another piece of evidence is that both GSTP1 and RASSF1A show high DNA methylation in circulating tumor cells or paired plasma-derived exosomes of mCRPC [80] and some genes related to androgen synthesis are also hypermethylated (such as CYP11A1, CYP11B1, CYP17A1 and CYP19A1) [81].