MGMT and oligodendroglioma: Recent years, based on molecular markers, such as IDH mutation, 1p/19q codeletion, Histone H3 K27M mutation, Histone H3.3 G34R/V mutation, MGMT et.al, diffuse gliomas were divided into oligodendroglioma IDH-mutation and 1p/19q codeletion, WHO grade II-III; Astrocytoma, IDH-mutation, WHO grade II-III; Astrocytoma, IDH-mutation, WHO grade IV; Glioblastomas, IDH wild type, MGMT promoter methylation, WHO grade IV; Diffuse hemispheric gliomas, H3.3 G34-mutant, MGMT promoter methylation, WHO grade IV; Diffuse midline gliomas, H3 K27M-mutant, WHO grade IV (2).