Overall, 31 of 31 CNS WHO grade 2 and 29 of 31 CNS WHO grade 3 tumors were assigned to the methylation class “astrocytoma, IDH-mutant, lower grade”, while 17 of 23 CNS WHO grade 4 tumors were assigned to the methylation class “astrocytoma, IDH-mutant, high-grade”. The gene discussed is IDH1; the disease is astrocytoma (excluding glioblastoma).