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Zwaig M, Baguette A, Hu B, Johnston M, Lakkis H, Nakada EM, Faury D, Juretic N, Ellezam B, Weil AG, Karamchandani J, Majewski J, Blanchette M, Taylor MD, Gallo M, Kleinman CL, Jabado N, Ragoussis J. Detection and genomic analysis of BRAF fusions in Juvenile Pilocytic Astrocytoma through the combination and integration of multi-omic data. BMC Cancer 2022; 22:1297. [PMID: 36503484 PMCID: PMC9743522 DOI: 10.1186/s12885-022-10359-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Accepted: 11/22/2022] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Juvenile Pilocytic Astrocytomas (JPAs) are one of the most common pediatric brain tumors, and they are driven by aberrant activation of the mitogen-activated protein kinase (MAPK) signaling pathway. RAF-fusions are the most common genetic alterations identified in JPAs, with the prototypical KIAA1549-BRAF fusion leading to loss of BRAF's auto-inhibitory domain and subsequent constitutive kinase activation. JPAs are highly vascular and show pervasive immune infiltration, which can lead to low tumor cell purity in clinical samples. This can result in gene fusions that are difficult to detect with conventional omics approaches including RNA-Seq. METHODS To this effect, we applied RNA-Seq as well as linked-read whole-genome sequencing and in situ Hi-C as new approaches to detect and characterize low-frequency gene fusions at the genomic, transcriptomic and spatial level. RESULTS Integration of these datasets allowed the identification and detailed characterization of two novel BRAF fusion partners, PTPRZ1 and TOP2B, in addition to the canonical fusion with partner KIAA1549. Additionally, our Hi-C datasets enabled investigations of 3D genome architecture in JPAs which showed a high level of correlation in 3D compartment annotations between JPAs compared to other pediatric tumors, and high similarity to normal adult astrocytes. We detected interactions between BRAF and its fusion partners exclusively in tumor samples containing BRAF fusions. CONCLUSIONS We demonstrate the power of integrating multi-omic datasets to identify low frequency fusions and characterize the JPA genome at high resolution. We suggest that linked-reads and Hi-C could be used in clinic for the detection and characterization of JPAs.
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Affiliation(s)
- Melissa Zwaig
- grid.14709.3b0000 0004 1936 8649McGill Genome Centre and Department of Human Genetics, McGill University, Montreal, Canada
| | - Audrey Baguette
- grid.414980.00000 0000 9401 2774Quantitative Life Sciences and Lady Davis Institute for Medical Research, Montreal, Quebec Canada
| | - Bo Hu
- grid.14709.3b0000 0004 1936 8649McGill Genome Centre and Department of Human Genetics, McGill University, Montreal, Canada
| | - Michael Johnston
- grid.22072.350000 0004 1936 7697Alberta Children‘s Hospital Research Institute, Charbonneau Cancer Institute, and Department of Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, AB Canada
| | - Hussein Lakkis
- grid.414980.00000 0000 9401 2774Department of Human Genetics and Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, Quebec Canada
| | - Emily M. Nakada
- grid.63984.300000 0000 9064 4811The Research Institute of the McGill University Health Centre, Montreal, Canada
| | - Damien Faury
- grid.63984.300000 0000 9064 4811The Research Institute of the McGill University Health Centre, Montreal, Canada
| | - Nikoleta Juretic
- grid.63984.300000 0000 9064 4811The Research Institute of the McGill University Health Centre, Montreal, Canada
| | - Benjamin Ellezam
- grid.14848.310000 0001 2292 3357Department of Pathology, Centre Hospitalier Universitaire Sainte-Justine, Université de Montréal, Montréal, QC, H3T 1C5 Canada
| | - Alexandre G. Weil
- grid.14848.310000 0001 2292 3357Department of Pediatric Neurosurgery, Centre Hospitalier Universitaire Sainte-Justine, Université de Montréal, Montréal, QC H3T 1C5 Canada
| | - Jason Karamchandani
- grid.14709.3b0000 0004 1936 8649Department of Pathology, Montreal Neurological Institute, McGill University, Montreal, QC H3A 2B4 Canada
| | - Jacek Majewski
- grid.14709.3b0000 0004 1936 8649McGill Genome Centre and Department of Human Genetics, McGill University, Montreal, Canada
| | - Mathieu Blanchette
- grid.14709.3b0000 0004 1936 8649School of Computer Science and McGill Center for Bioinformatics, McGill University, Montréal, Québec Canada
| | - Michael D. Taylor
- grid.42327.300000 0004 0473 9646Arthur and Sonia Labatt Brain Tumour Research Centre, Hospital for Sick Children Research Institute, Toronto, Canada
| | - Marco Gallo
- grid.22072.350000 0004 1936 7697Alberta Children‘s Hospital Research Institute, Charbonneau Cancer Institute, and Department of Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, AB Canada
| | - Claudia L. Kleinman
- grid.414980.00000 0000 9401 2774Department of Human Genetics and Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, Quebec Canada
| | - Nada Jabado
- grid.63984.300000 0000 9064 4811Department of Human Genetics, Department of Pediatrics, and The Research Institute of the McGill University Health Centre, Montreal, Canada
| | - Jiannis Ragoussis
- grid.14709.3b0000 0004 1936 8649McGill Genome Centre and Department of Human Genetics, McGill University, Montreal, Canada
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