MGMT and glioblastoma: Among them, the prodrug temozolomide (TMZ) with its active metabolite 5-(3-methyl-1-triazene-1-yl)imidazole-4-carboxamide) (MITC) is a first-line therapy for primary and recurrent GBM, especially O6-methylguanine-DNA methyltransferase (MGMT)-promotor-methylated tumors.