Gliomas in people with NF1 show alterations in the RAS/MAPK pathway, generally in the absence of BRAF alterations (common to sporadic pilocytic astrocytomas) or IDH or histone H3 mutations (common to diffuse gliomas subsets).
No significant differences regarding additional imaging features emerged between BRAFV600E-mutant and wild-type lesions, with the exception of the number of tumors with cystic components, significantly higher in BRAFV600E-mutant PAs (p = 0.011) CONCLUSION: Assessment of the DWI characteristics of GGs and PAs may assist in predicting BRAFV600E status, suggesting a radiogenomic correlation and prompt molecular characterization of these tumors.
KIAA1549-BRAF is the most frequently identified genetic mutation in sporadic pilocytic astrocytoma (PA), creating a fusion BRAF (f-BRAF) protein with increased BRAF activity.
More recently, cases of PA with gangliocytic differentiation (PA-GD) have been described, and these cases are thus far restricted to those with the KIAA1549-BRAF fusion.
The review of imaging features indicated that cyst formation is associated with the existence of KIAA1549-BRAF fusion in PA and GG and the lack of BRAF mutation in GG.
Our results further emphasize the importance of BRAF alterations in PA and the need to characterize them in a given tumor as this can affect therapeutic strategies and their potential use as tumor marker in molecular diagnostics.
Pilocytic astrocytomas are grade 1 tumors usually occurring in children and young adults with KIAA1549-BRAF fusion defining the majority of pilocytic astrocytomas.
We report actionable targets, including frequent FGFR1 mutation in optic-pathway PA that makes them excellent candidates to anti-FGFR therapies, and BRAF non-canonical mutations in PA.
A Multiplex Quantitative Reverse Transcription Polymerase Chain Reaction Assay for the Detection of KIAA1549-BRAF Fusion Transcripts in Formalin-Fixed Paraffin-Embedded Pilocytic Astrocytomas.
Correlation between magnetic resonance imaging characteristics and BRAF alteration status in individuals with optic pathway/hypothalamic pilocytic astrocytomas.
Genetic mechanisms such as activation of MAPK, BRAF gene deregulation and neurofibromatosis type 1 (NF1) syndrome have been associated with PA development.
BRAF fusion involving the KIAA1549 gene is a hallmark of pilocytic astrocytoma, but it has also been recorded in rare cases of gangliogliomas, 1p/19q co-deleted oligodendroglial tumors, and it is also a common feature of disseminated oligodendroglial-like leptomeningeal neoplasm.
BRAF-V600E mutations are most commonly found in pleomorphic xanthoastrocytoma, ganglioglioma, epithelioid glioblastoma, and gliomas diagnosed at a younger age; BRAF-KIAA1549 fusion is the most common BRAF alteration in pilocytic astrocytoma.
Abnormalities in proto-oncogene B-Raf (BRAF) are typical in several subgroups of gliomas, including pilocytic astrocytomas, optic nerve gliomas, pleomorphic xanthoastrocytomas (PXA), anaplastic PXAs and gangliogliomas.
BRAF mutations are most frequently detected in certain subtypes of low-grade glioma, such as pilocytic astrocytoma (PA), pleomorphic xanthoastrocytoma (PXA), ganglioglioma (GG) and dysembryoplastic neuroepithelial tumor (DNT).
The mitogen-activating protein kinase (MAPK) pathway and, more specifically, BRAF mutations have been shown to be prevalent in pediatric pilocytic astrocytomas and may represent one such area to target.
Using a combined analysis of RNA sequencing and copy number variation data we identified a new BRAF fusion involving the 5' gene fusion partner GTF2I (7q11.23), not previously described in PA.