GSTP1 and breast cancer: Moreover, the current results revealed that hypermethylation of genes involved in cell cycle regulation and apoptosis (CDKN2A, PYCARD, RASSF1), angiogenesis and metastasis (THBS1), DNA repair (BRCA1, MGMT), histone methylation (GSTP) and tumor suppressor genes (PTEN, HIC1) were significantly associated with worse DFS and OS rates in the whole group of BC patients.