IDH2 and astrocytoma (excluding glioblastoma): These lower-grade IDH-wildtype astrocytomas frequently have specific molecular alterations characteristic of IDH-wildtype glioblastoma, including high frequency of EGFR amplification, combined gain of chromosome 7 with loss of chromosome 10 (7+/10−), TERTp mutation, and tumors with these three factors have similar outcomes to IDH-wildtype glioblastoma, while lower-grade tumors without these characteristic alterations have significantly better clinical outcomes [36,43,88,126,127,128,129].