IDH2 and astrocytoma (excluding glioblastoma): Of the included 18 cases, 8 cases were from outside clients and 10 were in-house patients; they had been diagnosed as GBM, IDH-wildtype, WHO grade 4 (n = 14), GBM, IDH-wildtype arising from a previously diagnosed low-grade glioneuronal tumor (n = 1), IDH-mutant astrocytoma (n = 2), and a high-grade glial neoplasm, NOS (n = 1).