IDH1 and glioblastoma: 1) Adult-type diffuse gliomas (the majority of primary brain tumors, including (a) Astrocytoma, isocitrate dehydrogenase (IDH)-mutant, (b) Oligodendroglioma, IDH-mutant and 1p/19q-codeleted, (c) glioblastoma multiforme (GBM), IDH-wild type)