IDH1 and glioblastoma: According to WHO CNS5, if methylation profiling and integrated diagnostic data support a glioblastoma-type methylation class or demonstrate characteristic glioblastoma-associated molecular alterations, the tumor should be designated as ‘Glioblastoma, IDH-wildtype, WHO grade 4,’ rather than ‘Diffuse astrocytic glioma, IDH-wildtype, with molecular features of glioblastoma.’ The latter terminology is obsolete and no longer used in contemporary practice (66).