TERT promoter mutation status is necessary and sufficient to diagnose IDH-wildtype diffuse astrocytic glioma with molecular features of glioblastoma

The Consortium to Inform Molecular and Practical Approaches to CNS Tumor Taxonomy (cIMPACT-NOW) update 3 recommends that histologic grade II and III IDH -wildtype diffuse astrocytic gliomas that harbor EGFR amplification, the combination of whole chromosome 7 gain and whole chromosome 10 loss (7 + /10 −), or TERT promoter (p TERT ) mutations should be considered as glioblastomas (GBM), World Health Organization grade IV. In this retrospective study, we examined the utility of molecular classification based on p TERT status and copy-number alterations (CNAs) in IDH -wildtype lower grade gliomas (LGGs, grade II, and III). The impact on survival was evaluated for the p TERT mutation and CNAs, including EGFR gain/amplification, PTEN loss, CDKN2A homozygous deletion, and PDGFRA gain/amplification. We analyzed 46 patients with IDH -wildtype/p TERT -mutant (mut) LGGs and 85 with IDH -wildtype/p TERT -wildtype LGGs. EGFR amplification and a combination of EGFR gain and PTEN loss ( EGFR + / PTEN −) were significantly more frequent in p TERT -mut patients ( p