IDH1 and oligodendroglioma: The number of cases (number of recurrent cases is described in the parentheses) was as follows: 19 isocitrate dehydrogenase (IDH)-mutant (mt) astrocytoma 11 (3) cases of grade 3 and 8 (5) cases of grade 4; 49 (12) IDH-wild type (wt) GBM; 6 (0) IDH-wt diffuse astrocytoma; 6 (0) diffuse midline glioma, H3 K27-altered; 23 oligodendroglioma, 6 (0) cases of grade 2 and 17 (6) cases of grade 3; 1 (0) pilocytic astrocytoma.