The fifth edition of the WHO Classification of Tumors of the Central Nervous System (WHO CNS5) emphasizes the important role of molecular biomarkers in the diagnosis of GBM and defines GBM as an IDH-wild-type diffuse and astrocytic glioma in adults accompanied by microvascular proliferation or necrosis or TERT promoter mutation or EGFR gene amplification or +7/−10 chromosome copy number changes (GBM, IDH wildtype) to distinguish it from astrocytoma, IDH-mutant [2, 3]. Here, TERT is linked to glioblastoma.