Patients with IDH-mutant and 1p19q codeleted gliomas (oligodendrogliomas) have a median OS of about17 years for grade 2 tumors and 11 years for grade 3, longer than survival outcomes reported in patients with IDH mutant non-codeleted astrocytomas (mOS of approximately 8–9 years) [11,12,18,19,20,21,22,23,24,25,26,27]. The gene discussed is IDH2; the disease is oligodendroglioma.