IDH2 and astrocytoma (excluding glioblastoma): Adult-type diffuse gliomas account majority of gliomas and comprise three types of tumors: oligodendrogliomas, which are IDH-mutant and 1p/19q co-deleted, having the best prognosis; IDH-mutant astrocytomas with an intermediate outcome; and IDH-wildtype glioblastomas, which are associated with poor prognosis (1, 2).