MGMT and glioblastoma: In GBM, the most common genetic alterations are the mutation of the enzyme isocitrate dehydrogenase (IDH) of which IDHmut tumors present a better prognosis; with the unmethylation of the 8-methylguanosine methyltransferase (MGMT) promoter, GBM with methylated MGMT show a better prognosis than that with unmethylated MGMT and EGFR amplification [130].