This study demonstrates that the newly defined entity of mGBM, formally known as “diffuse astrocytic glioma, IDH-wildtype with molecular features of glioblastoma, WHO grade IV,” likely comprises of a small proportion of all IDH-wildtype GBM and may have slightly better clinical outcomes than histological IDH-wildtype GBM when adjusted for known prognostic factors. This evidence concerns the gene IDH1 and glioblastoma.