Frequent FGFR1 hotspot alterations in driver-unknown low-grade glioma and mixed neuronal-glial tumors.

Abstract

PURPOSE:

Low-grade gliomas (LGG) and mixed neuronal-glial tumors (MNGT) show frequent MAPK pathway alterations. Oncogenic fibroblast growth factor receptor 1 (FGFR1) tyrosinase kinase domain has been reported in brain tumors of various histologies. We sought to determine the frequency of FGFR1 hotspot mutations N546 and K656 in driver-unknown LGG/MNGT and examined FGFR1 immunohistochemistry as a potential tool to detect those alterations.

METHODS:

We analyzed 476 LGG/MNGT tumors for KIAA-1549-BRAF fusion, IDH1/2, TERT promotor, NF1, H3F3A and the remaining cases for FGFR1 mutation frequency and correlated FGFR1 immunohistochemistry in 106 cases.

RESULTS:

368 of 476 LGG/MNGT tumors contained non-FGFR1 alterations. We identified 9 FGFR1 p.N546K and 4 FGFR1 p.K656E mutations among the 108 remaining driver-unknown samples. Five tumors were classified as dysembryoplastic neuroepithelial tumor (DNT), 4 as pilocytic astrocytoma (PA) and 3 as rosette-forming glioneuronal tumor (RGNT). FGFR1 mutations were associated with oligodendroglia-like cells, but not with age or tumor location. FGFR1 immunohistochemical expression was observed in 92 cases. FGFR1 immunoreactivity score was higher in PA and DNT compared to diffuse astrocytoma, but no correlation between FGFR1 mutation in tumors and FGFR1 expression level was observed.

CONCLUSION:

FGFR1 hotspot mutations are the fifth most prevailing alteration in LGG/MNGT. Performing FGFR1 sequencing analysis in driver-unknown low-grade brain tumors could yield up to 12% FGFR1 N546/K656 mutant cases.

• Authors: Sophie Engelhardt, Felix Behling, Rudi Beschorner, Franziska Eckert, Patricia Kohlhof, Marcos Tatagiba, Ghazaleh Tabatabai, Martin U Schuhmann, Martin Ebinger, Jens Schittenhelm
• Journal: Journal of cancer research and clinical oncology (J Cancer Res Clin Oncol) Vol. 148 Issue 4 Pg. 857-866 (Apr 2022) ISSN: 1432-1335 [Electronic] Germany
• PMID: 35018490 (Publication Type: Journal Article)
• Copyright: © 2022. The Author(s).

Chemical References

• FGFR1 protein, human
• Receptor, Fibroblast Growth Factor, Type 1

Topics

• Astrocytoma (pathology)
• Brain Neoplasms (pathology)
• Child
• Glioma (genetics, pathology)
• Humans
• Mutation
• Oncogenes
• Receptor, Fibroblast Growth Factor, Type 1 (genetics)