Tumor-specific alterations were detected in 20% (4/20) of gliomas.GBM IDH-wt 12.5% (1/8)Gliosarcoma 0% (0/1)GBM IDH-mut 100% (1/1)AA 100% (2/2)DA 0% 0% (0/1)OD 50% 0% (0/4)DMG 100% 0% (0/3). The gene discussed is IDH2; the disease is gliosarcoma.