IDH1 and oligodendroglioma: A total number of 184 gliomas were included in this retrospective study with 101 glioblastomas (93 IDH-wildtype, 3 IDH-mutant, 5 NOS), 60 astrocytomas (22 IDH-wildtype, 37 IDH-mutant, 1 NOS), and 23 oligodendrogliomas (19 IDH-mutant and 1p/19q-codeleted, 4 NOS).