363 results match your criteria: "Arthur and Sonia Labatt Brain Tumour Research Centre[Affiliation]"

Glioblastoma is an incurable brain malignancy. By the time of clinical diagnosis, these tumours exhibit a degree of genetic and cellular heterogeneity that provides few clues to the mechanisms that initiate and drive gliomagenesis. Here, to explore the early steps in gliomagenesis, we utilized conditional gene deletion and lineage tracing in tumour mouse models, coupled with serial magnetic resonance imaging, to initiate and then closely track tumour formation.

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Background: Gliomas are a major cause of cancer-related death among children, adolescents, and young adults (age 0-40 years). Primary mismatch repair deficiency (MMRD) is a pan-cancer mechanism with unique biology and therapeutic opportunities. We aimed to determine the extent and impact of primary MMRD in gliomas among children, adolescents, and young adults.

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Stem cells perceive and respond to biochemical and physical signals to maintain homeostasis. Yet, it remains unclear how stem cells sense mechanical signals from their niche in vivo. In this work, we investigated the roles of PIEZO mechanosensitive channels in the intestinal stem cell (ISC) niche.

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Convection-enhanced delivery of [Lu]Lu-labeled gold nanoparticles combined with anti-PD1 checkpoint immunotherapy improves the survival of immunocompetent C57BL/6J mice with orthotopic GL261 murine glioma tumors.

Nucl Med Biol

November 2024

Department of Pharmaceutical Sciences, University of Toronto, Toronto, ON, Canada; Department of Medical Imaging, University of Toronto, Toronto, ON, Canada; Laboratory Medicine Program, University Health Network, Toronto, ON, Canada. Electronic address:

Introduction: Our objective was to study convection enhanced delivery (CED) of Lu-labeled metal chelating polymer (MCP) conjugated to gold nanoparticles ([Lu]Lu-MCP-AuNP) alone or combined with anti-PD1 immune checkpoint inhibition (ICI) for improving the survival of immunocompetent C57BL/6J mice with orthotopic GL261 murine glioma tumors.

Methods: C57BL/6J mice with GL261 tumors were treated with [Lu]Lu-MCP-AuNP (0.8 or 2.

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High detection rate of circulating-tumor DNA from cerebrospinal fluid of children with central nervous system germ cell tumors.

Acta Neuropathol Commun

November 2024

Division of Haematology/Oncology, The Hospital for Sick Children, 555 University Avenue, Toronto, ON, M5G 1X8, Canada.

Article Synopsis
  • * This study aimed to assess the detectability of circulating-tumor DNA (ctDNA) in cerebrospinal fluid (CSF) as a biomarker for monitoring CNS-GCT patients.
  • * Results showed that ctDNA could be detected in 89% of diagnostic samples, indicating its potential for non-invasive diagnosis and treatment response monitoring in future CNS-GCT research.
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  • * The research indicates that this viral mimicry is driven by increased expression of specific genes with intronic inverted-repeat Alu elements, rather than the activation of retroelements seen in other therapies.
  • * Additionally, EZH2 inhibition enhances the expression of LINE-1 retrotransposons, which contributes to genomic instability and activates immune signaling pathways, but simultaneously blocking dsRNA and DNA sensing prevents the viral mimicry effect in these tumors.
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Modulation of Stemness and Differentiation Regulators by Valproic Acid in Medulloblastoma.

bioRxiv

September 2024

Cancer and Neurobiology Laboratory, Experimental Research Center, Clinical Hospital (CPE-HCPA), Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil.

Article Synopsis
  • - Changes in epigenetic processes like histone acetylation are important for the function and progression of pediatric brain tumors, with drugs like valproic acid (VPA) showing potential as anticancer therapies by inhibiting histone deacetylases (HDACs).
  • - VPA treatment resulted in reduced viability of medulloblastoma (MB) cells, induced cell cycle arrest, and altered gene expression related to oncogenes and differentiation, alongside morphological changes that suggest neuronal differentiation.
  • - The effects of VPA on MB cells included modifications in histone acetylation patterns that correlated with patient outcomes, suggesting its potential to influence clinical prognosis by targeting stemness and differentiation in specific MB subgroups.
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  • Brain metastases (BMs) are the most common and lethal brain tumors, primarily originating from lung adenocarcinoma (LUAD), yet reliable predictors for their development are currently lacking.
  • Researchers analyzed 402 tumor and plasma samples from LUAD patients to create a predictive model based on DNA methylation signatures, combining it with clinical data for personalized risk assessments of developing BMs.
  • The study also identified unique genetic markers and immune cell changes that could aid in early detection of BMs through non-invasive tests, enhancing the potential for targeted and effective treatments.
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Molecular markers for pediatric low-grade glioma.

Childs Nerv Syst

October 2024

Department of Pediatric Laboratory Medicine, Hospital for Sick Children, Toronto, ON, Canada.

Article Synopsis
  • Recent research has significantly improved our knowledge of the genetic factors driving pediatric low-grade glioma (PLGG), mainly focusing on the RAS/MAPK pathway.
  • Key genetic alterations, especially in genes like BRAF, FGFR1, and NF1, play crucial roles in these tumors, with additional mutations in tumor suppressor genes potentially leading to more aggressive forms.
  • Comprehensive genetic profiling, including sequencing and copy number analysis, is essential for accurate diagnosis and treatment planning for PLGG.
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A peptide encoded by upstream open reading frame of binds to tropomyosin receptor kinase B and promotes glioblastoma growth in mice.

Sci Transl Med

October 2024

National Health Commission Key Laboratory of Antibody Techniques, Department of Cell Biology, Jiangsu Provincial Key Laboratory of Human Functional Genomics, School of Basic Medical Sciences, Nanjing Medical University, Nanjing, Jiangsu 211166, China.

MYC promotes tumor growth through multiple mechanisms. Here, we show that, in human glioblastomas, the variant transcript encodes a 114-amino acid peptide, MYC pre-mRNA encoded protein (MPEP), from the upstream open reading frame (uORF) . Secreted MPEP promotes patient-derived xenograft tumor growth in vivo, independent of MYC through direct binding, and activation of tropomyosin receptor kinase B (TRKB), which induces downstream AKT-mTOR signaling.

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Diffuse intrinsic pontine glioma (DIPG) remains a significant therapeutic challenge due to the lack of effective and safe treatment options. This study explores the potential of combining histone deacetylase (HDAC) and carbonic anhydrase 9 (CA9) inhibitors in treating DIPG. Analysis of RNA sequencing data and tumor tissue from patient samples for the expression of the carbonic anhydrase family and hypoxia signaling pathway activity revealed clinical relevance for targeting CA9 in DIPG.

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Background: Constitutional mismatch repair deficiency syndrome (CMMRD) is a rare childhood cancer predisposition syndrome associated with a broad spectrum of malignancies, including non-Hodgkin lymphomas (NHL). Most patients die due to cancer before the age of 20 years. Limited data exist on CMMRD-associated lymphomas and their outcome.

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Article Synopsis
  • Treatment for meningiomas primarily involves surgery and sometimes radiation, but patient responses can vary significantly.
  • Researchers analyzed data from 2,824 meningiomas, including both retrospective and prospective information, to identify molecular biomarkers that predict treatment response.
  • The study found that complete tumor removal and proper treatment of the dural margin significantly improve survival rates, and developed a new molecular model that better predicts how patients will respond to radiotherapy compared to traditional classification methods.
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Background: Few studies have characterized the burden of late effects among childhood ependymoma survivors. To address this gap, we examined these sequelae using real-world health services data in a population-based ependymoma survivor cohort.

Methods: All individuals younger than 18 years diagnosed with an ependymoma in Ontario, Canada between 1987 and 2015 who had survived at least 5 years from their latest pediatric cancer event (index date) were matched 1:5 with population controls.

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Leading medulloblastoma to a differentiation end.

Cancer Cell

August 2024

Program in Developmental and Stem Cell Biology, Arthur and Sonia Labatt Brain Tumour Research Centre, Hospital for Sick Children, Toronto, ON, Canada; Division of Haematology/Oncology, Hospital for Sick Children, Toronto, ON, Canada; Departments of Medical Biophysics and Paediatrics, University of Toronto, Toronto, ON, Canada. Electronic address:

Effective and less toxic therapies for medulloblastoma have proved to be highly elusive. In this issue of Cancer Cell, Yang et al. show that thyroid hormone treatment leads to the activation of neurogenic differentiation factor 1 (NeuroD1) and differentiation of medulloblastoma cells through reversing EZH2-mediated transcriptional repression of NeuroD1.

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Pineal parenchymal tumors are rare neoplasms for which evidence-based treatment recommendations are lacking. These tumors vary in biology, clinical characteristics, and prognosis, requiring treatment that ranges from surgical resection alone to intensive multimodal antineoplastic therapy. Recently, international collaborative studies have shed light on the genomic landscape of these tumors, leading to refinement in molecular-based disease classification in the 5th edition of the World Health Organization (WHO) classification of tumors of the central nervous system.

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A group 3 medulloblastoma stem cell program is maintained by OTX2-mediated alternative splicing.

Nat Cell Biol

August 2024

Department of Biochemistry and Medical Genetics, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada.

OTX2 is a transcription factor and known driver in medulloblastoma (MB), where it is amplified in a subset of tumours and overexpressed in most cases of group 3 and group 4 MB. Here we demonstrate a noncanonical role for OTX2 in group 3 MB alternative splicing. OTX2 associates with the large assembly of splicing regulators complex through protein-protein interactions and regulates a stem cell splicing program.

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With the success of immunotherapy in cancer, understanding the tumor immune microenvironment (TIME) has become increasingly important; however in pediatric brain tumors this remains poorly characterized. Accordingly, we developed a clinical immune-oncology gene expression assay and used it to profile a diverse range of 1382 samples with detailed clinical and molecular annotation. In low-grade gliomas we identify distinct patterns of immune activation with prognostic significance in BRAF V600E-mutant tumors.

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Early rhombic lip Protogenin stem cells in a human-specific neurovascular niche initiate and maintain group 3 medulloblastoma.

Cell

August 2024

The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, ON, Canada; Developmental & Stem Cell Biology Program, The Hospital for Sick Children, Toronto, ON, Canada; Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada; Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada; Texas Children's Cancer and Hematology Center, Houston, TX, USA; Department of Pediatrics - Hematology/Oncology, Baylor College of Medicine, Houston, TX, USA; Department of Neurosurgery, Baylor College of Medicine, Houston, TX, USA; Department of Neurosurgery, Texas Children's Hospital, Houston, TX, USA; Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, TX, USA; Department of Surgery, University of Toronto, Toronto, ON, Canada. Electronic address:

We identify a population of Protogenin-positive (PRTG) MYC NESTIN stem cells in the four-week-old human embryonic hindbrain that subsequently localizes to the ventricular zone of the rhombic lip (RL). Oncogenic transformation of early Prtg rhombic lip stem cells initiates group 3 medulloblastoma (Gr3-MB)-like tumors. PRTG stem cells grow adjacent to a human-specific interposed vascular plexus in the RL, a phenotype that is recapitulated in Gr3-MB but not in other types of medulloblastoma.

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Leptomeningeal metastases (LM) are increasingly becoming recognized as a treatable, yet generally incurable, complication of advanced cancer. As modern cancer therapeutics have prolonged the lives of patients with metastatic cancer, specifically in patients with parenchymal brain metastases, treatment options, and clinical research protocols for patients with LM from solid tumors have similarly evolved to improve survival within specific populations. Recent expansions in clinical investigation, early diagnosis, and drug development have given rise to new unanswered questions.

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Mutations accumulate in the genome of every cell of the body throughout life, causing cancer and other diseases. Most mutations begin as nucleotide mismatches or damage in one of the two strands of the DNA before becoming double-strand mutations if unrepaired or misrepaired. However, current DNA-sequencing technologies cannot accurately resolve these initial single-strand events.

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Replication repair deficiency (RRD) is a pan-cancer mechanism characterized by abnormalities in the DNA mismatch repair (MMR) system due to pathogenic variants in the PMS2, MSH6, MSH2, or MLH1 genes, and/or in the polymerase-proofreading genes POLE and POLD1. RRD predisposition syndromes (constitutional MMR deficiency, Lynch, and polymerase proofreading-associated polyposis) share overlapping phenotypic and biological characteristics. Moreover, cancers stemming from germline defects of one mechanism can acquire somatic defects in another, leading to complete RRD.

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Diffuse intrinsic pontine glioma (DIPG) is an aggressive brain tumour that occurs in the pons of the brainstem and accounts for over 80% of all brainstem gliomas. The median age at diagnosis is 6-7 years old, with less than 10% overall survival 2 years after diagnosis and less than 1% after 5 years. DIPGs are surgically inaccessible, and radiation therapy provides only transient benefit, with death ensuing from relentless local tumour infiltration.

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