TERT and glioblastoma: Activation of telomerase, encoded by the TERT gene, is a key step in oncogenesis as persistent maintenance of telomere length prevents normal cell aging and promotes cell immortality.18 The c.-124C>T variant is a “hotspot” mutation of the TERT promoter documented in multiple cancer types, including GBM, that results in increased transcription of the gene.19,20TERT promoter mutations have been associated with poor prognosis in IDH wild-type GBM.21 The described cauda equina lesion thus contains several genetic features expected to facilitate GBM growth.