IDH2 and central nervous system cancer: RAS-mutant gliomas accounted for 6.25% of cases of anaplastic astrocytoma, IDH-wildtype (2 of 32), 6.67% of anaplastic oligodendroglioma, IDH-mutant with 1p/19q codeletion (1 of 15), and all gangliogliomas (1 of 1).