MGMT and glioma: New tumor microenvironment-derived subtypes of GBM (Wang et al., 2017) and new markers related to epigenetic changes, such as the promoter methylation status of the DNA repair enzyme, O6-methylguanine-DNA-methyltransferase (MGMT), have been added to the pool of known markers of the glioma progression (Reifenberger et al., 2016).