Unlike IDH-wildtype glioblastoma or IDH-mutant and 1p/19q-codeleted oligodendroglioma, genomic identification of significant targets in cancer (GISTIC) algorithms highlight fewer chromosomal regions with well-defined and consistent alterations in IDH-mutant astrocytomas, instead showing a pattern of relatively random distribution of copy number alterations across the entire genome [71, 94, 96, 98]. Here, IDH2 is linked to oligodendroglioma.