MGMT and glioma: Categorization of gliomas previously focused on histological features (Bailey and Cushing, 1927); however, characterization methods have shifted toward high-resolution molecular profiling, including identification of isocitrate dehydrogenase (IDH) mutation, co-deletion of chromosomal arms, O6-methylguanine-DNA methyltransferase (MGMT) promoter methylation, and miR-181d expression (Jiang et al., 2016).