GSTP1 and cancer: Earlier studies focused on DNA methylation changes and mainly tested whether IF might be able to reverse cancer-associated aberrations in DNA methylation, especially silencing of TSGs such as RARβ2, BTG3, PTEN and ATM, genes involved in DNA repair (MGMT, BRCA1, BRCA2, GSTP1), cell signaling (especially Wnt-signaling in colon cancer), and cell cycle regulators (p16).