Additional genetic alterations in BRAF-mutant gliomas correlate with histologic diagnoses

Antonio Dono, Jennifer Vu, Molly Anapolsky, Gabriella Hines, Takeshi Takayasu, Yuanqing Yan, Nitin Tandon, Jay Jiguang Zhu, Meenakshi B. Bhattacharjee, Yoshua Esquenazi, Leomar Y. Ballester*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Introduction: Recently, the term “Diffuse glioma, BRAF V600E-mutant” has been recommended for IDH-wildtype gliomas with BRAF p.V600E mutation and without CDKN2A/B deletion. However, additional alterations in gliomas that coexist with BRAF-mutations are poorly defined. Methods: We analyzed next-generation sequencing results in 315 cancer-associated genes for 372 gliomas from our institution (2010 to 2017). In addition, we reviewed IDH-WT gliomas with mutation and copy-number alterations available in cBioPortal, to further characterize BRAF-mutant gliomas. Results: Seventeen (4.6%) showed BRAF mutations. Tumor types included 8 glioblastomas, 2 epithelioid glioblastomas (E-GBM), 2 pleomorphic xanthoastrocytomas (PXA), 1 anaplastic oligodendroglioma, 1 diffuse astrocytoma, and 3 pilocytic astrocytomas. Fifty-three percent (53%) of cases exhibited BRAF-alterations other than p.V600E. The majority of the tumors were localized in the temporal lobe (52.9%). In addition to BRAF mutations, glioblastomas showed concomitant mutations in TP53 (3/8), CDKN2A/B-loss (6/8), TERT-promoter (6/8), and/or PTEN (5/8). Both E-GBMs and PXAs showed CDKN2A/B-loss and BRAF p.V600E with absence of TERTp, TP53, and PTEN mutations. Similar findings were observed in BRAF-mutant infiltrating gliomas from cBioPortal. Conclusions: Knowledge of additional alterations that co-occur with BRAF-mutations in gliomas may improve diagnosis and help identify patients that could benefit from targeted therapies. Furthermore, we provide examples of two patients whose tumors responded to BRAF pathway inhibitors, arguing in favor of these therapies in patients with BRAF-mutant gliomas.

Original languageEnglish (US)
Pages (from-to)463-472
Number of pages10
JournalJournal of Neuro-Oncology
Volume149
Issue number3
DOIs
StatePublished - Sep 1 2020
Externally publishedYes

Keywords

  • BRAF mutant glioma
  • BRAF p.V600E
  • Cobimetinib
  • Epithelioid glioblastoma
  • PXA

ASJC Scopus subject areas

  • Oncology
  • Neurology
  • Clinical Neurology
  • Cancer Research

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