MGMT and glioblastoma: Indeed, a range of clinical trials have been focusing on molecular targets previously described as classical markers of GBM epigenetic signatures, such as O6-methylguanine–DNA methyltransferase (MGMT) gene methylation and histone posttranslational modifications (PTM), as putative epigenetic biomarkers for tumor diagnosis and sub-type classification, prognosis as well as for personalized therapeutical targets as an option for eligible patients (5).