In addition to the mutational status of IDH1/2 and enzymes involved in a variety of metabolic processes, such as the production of redox species and epigenetic mechanisms, and DNA repair [24,25,26,27], the 6-O-methylguanine DNA methyltransferase (MGMT), involved in DNA repair, is another key predictive and prognostic marker for the treatment of GBM [28]. Here, MGMT is linked to glioblastoma.