IDH1 and astrocytoma (excluding glioblastoma): The average copy number for CDKN2A was 1.09 ± 0.75 in IDH-wildtype infiltrating astrocytoma, 1.73 ± 0.68 in IDH-mutant infiltrating astrocytoma, and 1.94 ± 0.41 in oligodendroglioma.