Tumors were classified according to WHO CNS5 into three categories: oligodendroglioma, IDH-mutant, and 1p/19q co-deleted (n = 18); astrocytoma, IDH-mutant (n = 38); and glioblastoma, IDH-wildtype (n = 43). Here, IDH1 is linked to astrocytoma (excluding glioblastoma).