Project description:FGFR1 genetic alterations are associated with human diseases, including brain tumors. We reported multiple FGFR1 mutations in familial and sporadic cases of low-grade glioneuronal tumors, suggesting intrinsic mechanisms of selective pressure toward FGFR1 multiple events arising in the context of a quiet genome. To decipher the molecular mechanisms triggered by multiple FGFR1 mutations, we have mapped the proximal interactome of wild-type, single- and double-mutant FGFR1 proteins through a BioID-MS approach. Our data reveals novel oncogenic functionality for the two hotspots N546K and K656E, linked to evasion of lysosomal degradation. We identified a modulatory role played by the susceptibility variant R661P, which hampers the oncogenic potential of both hotspot mutations by rescuing receptor degradation and reducing N546K affinity for the downstream effector PLCγ. The R661P variant alone abolished the self-renewal capacity of oligodendroglioma cells and showed downregulation of genes involved in neurodevelopment and neuro-glial cell fate decisions, both aspects overcome in the double mutants. This study sheds light on the oncogenic effects associated with FGFR1 alterations and their recurrence in low-mutation burden and therapy naïve tumors.
Project description:Genome-wide DNA methylation profiling of 30 low-grade neuroepithelial tumors with FGFR1 alterations including rosette-forming glioneuronal tumor, pilocytic astrocytoma, dysembryoplastic neuroepithelial tumor, and extraventricular neurocytoma. The Illumina Infinium EPIC 850k Human DNA Methylation Beadchip was used to obtain DNA methylation profiles across approximately 850,000 CpG sites of genomic DNA extracted from formalin-fixed, paraffin-embedded tumor tissue of 30 low-grade neuroepithelial tumors with FGFR1 alterations including kinase domain tandem duplication, in-frame fusion with TACC1, and hotspot missense mutation within the intracellular tyrosine kinase domain.
Project description:The gene encoding fibroblast growth factor receptor 1 (FGFR1) amplification is associated with poor prognosis in estrogen receptor positive (ER+) breast cancer, and thus represents a potential therapeutic target. Fluorescent in situ hybridization (FISH) has been used as the gold standard methodology for detection of FGFR1 amplification, but it is a relatively long labor-intensive procedure and not efficient to process a large number of patient samples, especially formalin fixed paraffin embedded (FFPE) samples. This study sought to identify genes discriminative at the mRNA level for FGFR1 amplification and to construct a multi-gene test to facilitate efficient screening for FGFR1 amplified ER+ breast tumors.
Project description:As part of a larger study on disseminated pediatric low-grade gliomas, we performed scRNAseq on two diffuse leptomeningeal glioneuronal tumors (DLGNT), one of which remained low-grade, and the other of which underwent high-grade transformation. Using this data, we compared the cellular pathway activation of each tumor, identifying a subpopulation of highly proliferative tumor cells in the transformed sample, which had elevated MAPK pathway activity and depressed p53 pathway activity.
Project description:Glioneuronal tumor (GN) is one type of biphasic central nervous system (CNS) tumor that exhibits both glial and neuronal immunohistological characteristics. We report a case of glioneuronal tumor (GN) with a discovery of novel gene fusion of CLIP2-MET resulting from aberrant chromosome 7 abnormalities. The tumor exhibited typical characteristics on histological examinations. We executed an elaborate genomic study on this case including whole-exome sequencing and RNA sequencing. Genomic analysis of the tumor revealed aberrations in chromosomes 1 and 7 and a CLIP2-MET fusion. Further analysis of the upregulated genes revealed substantial connections with MAPK pathway activation. We concluded that the chromosome 7 abnormalities prompted CLIP2-MET gene fusion which successively leads to MAPK pathway activation. We deliberated that MAPK pathway activation is responsible for the oncogenesis of GN based on our case and other previously reported ones.
Project description:Diffuse midline glioma (DMG) is a devastating disease that is defined by its localization, by the diffuse growth of astrocytic tumor cells, and by K27M mutations within Histone H3 proteins. In a large series of such tumor samples (n=83), we show here that 12 % of these cases (n=10) harbor concomitant hotspot mutations within FGFR1 or BRAF. Respective cases were all located in midline structures and matched with reference cases of DMG using global DNA methylation profiling. TP53 mutations were significantly more frequent in BRAF/FGFR1 wild type cases. Presence of hotspot mutations within FGFR1 or BRAF was associated with a significantly better overall survival, which was independent of the patients’ age and tumor localization. Thus, our results establish the relevance of FGFR1 or BRAF mutations in DMG as a prognostic marker and open new targeted therapy options in this subgroup of DMG.