IDH1 and glioblastoma: IDH-wildtype diffuse astrocytic tumors without the histological features of GBM, which would have otherwise been classified as grade 2 or 3, are considered as molecular GBM (mol-GBM, WHO grade 4) if they harbor any of the following molecular abnormalities: TERT promoter mutation, EGFR amplification, or chromosomal + 7/−10 copy changes.