CDKN2A and oligodendroglioma: Histomorphology and molecular detection results revealed eight cases each of grades 2 and 3 oligodendroglioma carrying mutant IDH with the 1p/19q-codeletion; 18, 11, and 13 cases of grades 2, 3, and 4 astrocytoma carrying mutant IDH. One case of grade 2 astrocytoma with homozygous deletion of CDKN2A, according to the new tumor classification, this patient should be IDH-mutant, grade 4 (Figures 1D–F).