MGMT and oligodendroglioma: Among 246 samples assessed via DNA methylation array, 140 (57%) tested positive for MGMT promoter methylation (79 IDHwt GBMs, 32 IDHmut astrocytomas, 29 IDHmut oligodendrogliomas), while 106 (43%) tested negative (88 IDHwt GBMs, 18 IDHmut astrocytomas, 0 IDHmut oligodendrogliomas).