IDH1 and anaplastic oligodendroglioma: Thirty-seven tumors were IDH1-wildtype (36 glioblastomas, 1 anaplastic astrocytoma (2016), or glioblastoma (2021), 13 tumors were IDH1-mutant (1 glioblastoma (2016), or astrocytoma, grade IV (2021), 5 anaplastic astrocytomas, 7 anaplastic oligodendrogliomas).