According to the 2021 WHO classification, IDH-wildtype diffuse gliomas with a TERT promoter (TERTp) mutation, EGFR amplification, or combined whole-chromosome 7 gain and 10 loss (+ 7/− 10) are designated as GBM, IDH-wildtype, regardless of histological grade, and termed molecular GBM (mol-GBM). The gene discussed is TERT; the disease is glioblastoma.