IDH2 and central nervous system cancer: Also, a role for HIF-1α in IDH-mutated cancer pathogenesis has been questioned based on the fact that IDH-mutated gliomas are generally not “angiogenic” as would be expected for tumors with dysregulated HIF-1α [10], and because IDH-mutated leukemias were not found to have increased expression of HIF-1α target genes [5].