DOI: 10.1093/noajnl/vdae006 ISSN: 2632-2498

Alternative Lengthening of Telomeres (ALT) is seen in a proportion of oligodendrogliomas and is associated with a worse prognosis

Zhi-Feng Shi, Kay Ka-Wai Li, Danny Tat-Ming Chan, Ying Mao, Ho-Keung Ng
  • Surgery
  • Oncology
  • Neurology (clinical)


Oligodendrogliomas are known to be mutated for TERTp, and in this report, we evaluated 112 IDH-mutant, 1p19q codeleted oligodendrogliomas for ALT by FISH, and FISH for copy number changes of CDKN2A, MYC, PDGFRA, EGFR, chromosomes +7/10 and TERT-rearrangement. Enigmatically, 35.7% of cases were ALT-positive in spite of the vast majority of them being TERTp-mutant. ALT was associated with a shorter PFS (p=0.009) and remained an independent prognosticator in multivariate analysis. ALT was also associated with MYC amplification. ALT-positive cases were further examined with targeted sequencing. No genes were found to be of prognostic significance in this group.

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