IDH1 and oligodendroglioma: Typically, the aforementioned first two categories, “astrocytoma, IDH-mutant,” and “oligodendroglioma, IDH-mutant, 1p19q-codeletion,” are classified as “low-grade gliomas,” whereas glioblastomas are categorized as “high-grade gliomas” (Louis et al., 2021; Li et al., 2022).