IDH1 and oligodendroglioma: IDH1, R132H, and H3K27M immunohistochemistry (IHC) staining showed that the glioma cases contained pilocytic astrocytoma, diffuse astrocytoma with/without IDH-mutant, anaplastic astrocytomas with/without IDH-mutant, oligodendrogliomas, anaplastic oligodendrogliomas, glioblastomas with/without IDH-mutant, and diffuse midline glioma H3K27M-mutant (Table 1).