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Recurrent somatic BRAF insertion (p.V504_R506dup): a tumor marker and a potential therapeutic target in pilocytic astrocytoma. Oncogene 2018; 38:2994-3002. [PMID: 30575814 PMCID: PMC6484687 DOI: 10.1038/s41388-018-0623-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 09/10/2018] [Accepted: 11/23/2018] [Indexed: 12/19/2022]
Abstract
Pilocytic astrocytoma (PA) is emerging as a tumor entity with dysregulated RAS/RAF/MEK/ERK signaling. In this study, we report the identification of a novel recurrent BRAF insertion (p.V504_R506dup) in five PA cases harboring exclusively this somatic tandem duplication. This recurrent alteration leads to an addition of three amino acids in the kinase domain of BRAF and has functional impact on activating MAPK phosphorylation. Importantly, we show that this mutation confers resistance to RAF inhibitors without changing effectiveness while downstream MEK inhibitors remain effective. 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.
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Abstract
The WHO grading scheme for glial neoplasms assigns Grade II to 5 distinct tumors of astrocytic or oligodendroglial lineage: diffuse astrocytoma, oligodendroglioma, oligoastrocytoma, pleomorphic xanthoastrocytoma, and pilomyxoid astrocytoma. Although commonly referred to collectively as among the "low-grade gliomas," these 5 tumors represent molecularly and clinically unique entities. Each is the subject of active basic research aimed at developing a more complete understanding of its molecular biology, and the pace of such research continues to accelerate. Additionally, because managing and predicting the course of these tumors has historically proven challenging, translational research regarding Grade II gliomas continues in the hopes of identifying novel molecular features that can better inform diagnostic, prognostic, and therapeutic strategies. Unfortunately, the basic and translational literature regarding the molecular biology of WHO Grade II gliomas remains nebulous. The authors' goal for this review was to present a comprehensive discussion of current knowledge regarding the molecular characteristics of these 5 WHO Grade II tumors on the chromosomal, genomic, and epigenomic levels. Additionally, they discuss the emerging evidence suggesting molecular differences between adult and pediatric Grade II gliomas. Finally, they present an overview of current strategies for using molecular data to classify low-grade gliomas into clinically relevant categories based on tumor biology.
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Affiliation(s)
- Nicholas F Marko
- Department of Neurosurgery, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA.
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3
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Bergthold G, Bandopadhayay P, Bi WL, Ramkissoon L, Stiles C, Segal RA, Beroukhim R, Ligon KL, Grill J, Kieran MW. Pediatric low-grade gliomas: how modern biology reshapes the clinical field. Biochim Biophys Acta Rev Cancer 2014; 1845:294-307. [PMID: 24589977 DOI: 10.1016/j.bbcan.2014.02.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Accepted: 02/20/2014] [Indexed: 12/17/2022]
Abstract
Low-grade gliomas represent the most frequent brain tumors arising during childhood. They are characterized by a broad and heterogeneous group of tumors that are currently classified by the WHO according to their morphological appearance. Here we review the clinical features of these tumors, current therapeutic strategies and the recent discovery of genomic alterations characteristic to these tumors. We further explore how these recent biological findings stand to transform the treatment for these tumors and impact the diagnostic criteria for pediatric low-grade gliomas.
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Affiliation(s)
| | - Pratiti Bandopadhayay
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA; Division of Pediatric Hematology and Oncology, Dana-Farber Cancer Institute, Boston, MA, USA; Boston Children's Hospital, Boston, MA, USA
| | - Wenya Linda Bi
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Lori Ramkissoon
- Department of Pathology, Brigham and Women's Hospital, Boston, MA, USA; Center for Molecular Oncologic Pathology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Charles Stiles
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Rosalind A Segal
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA; Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Rameen Beroukhim
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Keith L Ligon
- Department of Pathology, Brigham and Women's Hospital, Boston, MA, USA; Center for Molecular Oncologic Pathology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Jacques Grill
- Departement de Cancerologie de l'enfant et de l'adolescent, Gustave Roussy and Unité Mixte de Recherche 8203 du Centre National de la Recherche Scientifique, Université Paris-Sud, Villejuif, France
| | - Mark W Kieran
- Center for Molecular Oncologic Pathology, Dana-Farber Cancer Institute, Boston, MA, USA; Center for Molecular Oncologic Pathology, Dana-Farber Cancer Institute, Boston, MA, USA.
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Kim JH, Huse JT, Huang Y, Lyden D, Greenfield JP. Molecular diagnostics in paediatric glial tumours. Lancet Oncol 2013; 14:e19-27. [PMID: 23276367 DOI: 10.1016/s1470-2045(12)70577-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Glial tumours in children have distinct patterns of epigenetic alteration, chromosomal structure, and gene and protein expression that differentiate them from their histological counterparts in adults. Understanding paediatric gliomas at the molecular level provides important prognostic and therapeutic insights, such as which genetic alterations confer a favourable response to adjuvant therapy, or which signalling pathways might be amenable to specific molecularly targeted agents. For clinicians, the ultimate goal is to individualise therapeutic regimens on the basis of the molecular fingerprint of a particular tumour and the prognosis conferred by this profile. In this Review, we examine a series of studies of molecular and genomic analysis of glial tumours in children, and discuss the many clinical insights that these molecular features provide.
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Affiliation(s)
- Joon-Hyung Kim
- Department of Neurological Surgery, Weill Cornell Medical College, New York, NY 10065, USA
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5
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Abstract
Primary glial brain tumors account for the majority of primary brain tumors in children. They are classified as low-grade gliomas (LGG) or high-grade gliomas (HGG), based on specific pathologic characteristics of the tumor, resulting in disparate clinical prognoses. Surgery is a mainstay of treatment for HGG, although it is not curative, and adjuvant therapy is required. Temozolomide, an oral imidazotetrazine prodrug, while considered standard of care for adult HGG, has not shown the same degree of benefit in the treatment of pediatric HGG. There are significant biologic differences that exist between adult and pediatric HGG, and targets specifically aimed at the biology in the pediatric population are required. Novel and specific therapies currently being investigated for pediatric HGG include small molecule inhibitors of epidermal growth factor receptor, platelet-derived growth factor receptor, histone deacetylase, the RAS/AKT pathway, telomerase, integrin, insulin-like growth factor receptor, and γ-secretase. Surgery is also the mainstay for LGG. There are defined front-line, multiagent chemotherapy regimens, but there are few proven second-line chemotherapy options for refractory patients. Approaches such as the inhibition of the mammalian target of rapamycin pathway, inhibition of MEK1 and 2, as well as BRAF, are discussed. Further research is required to understand the biology of pediatric gliomas as well as the use of molecularly targeted agents, especially in patients with surgically unresectable tumors.
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Abstract
The term long-term epilepsy associated tumor (LEAT) encompasses lesions identified in patients investigated for long histories (often 2 years or more) of drug-resistant epilepsy. They are generally slowly growing, low grade, cortically based tumors, more often arising in younger age groups and in many cases exhibit neuronal in addition to glial differentiation. Gangliogliomas and dysembryoplastic neuroepithelial tumors predominate in this group. LEATs are further united by cyto-architectural changes that may be present in the adjacent cortex which have some similarities to developmental focal cortical dysplasias (FCD); these are now grouped as FCD type IIIb in the updated International League Against Epilepsy (ILAE) classification. In the majority of cases, surgical treatments are beneficial from both perspectives of managing the seizures and the tumor. However, in a minority, seizures may recur, tumors may show regrowth or recurrence, and rarely undergo anaplastic progression. Predicting and identifying tumors likely to behave less favorably are key objectives of the neuropathologist. With immunohistochemistry and modern molecular pathology, it is becoming increasingly possible to refine diagnostic groups. Despite this, some LEATs remain difficult to classify, particularly tumors with "non-specific" or diffuse growth patterns. Modification of LEAT classification is inevitable with the goal of unifying terminological criteria applied between centers for accurate clinico-pathological-molecular correlative data to emerge. Finally, establishing the epileptogenic components of LEAT, either within the lesion or perilesional cortex, will elucidate the cellular mechanisms of epileptogenesis, which in turn will guide optimal surgical management of these lesions.
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Affiliation(s)
- Maria Thom
- Department of Clinical and Experimental Epilepsy, UCL, Institute of Neurology, Queen Square, London, UK.
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Valera ET, Brassesco MS, Scrideli CA, de Castro Barros MV, Santos AC, Oliveira RS, Machado HR, Tone LG. Are patients with encephalocraniocutaneous lipomatosis at increased risk of developing low-grade gliomas? Childs Nerv Syst 2012; 28:19-22. [PMID: 21983849 DOI: 10.1007/s00381-011-1601-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2011] [Accepted: 09/26/2011] [Indexed: 11/27/2022]
Abstract
INTRODUCTION Cancer-prone genetic disorders are responsible for brain tumors in a considerable proportion of children. Additionally, rare genetic syndromes associated to cancer development may potentially disclose genetic mechanisms related to oncogenesis. METHOD We describe two pediatric patients with encephalocraniocutaneous lipomatosis (ECCL), a very rare genetic syndrome with around 60 reported cases, which developed low-grade astrocytoma at 3 and 12 years of age. RESULTS Patients with ECCL seem to be at risk of benign forms of osseous tumors such as ossifying fibromas, odontomas, and osteomas. CONCLUSION The association between brain tumor and ECCL was previously reported only once, in a pediatric case of a mixed neuronal-glial histology. Whether ECCL may be a genetic condition of predisposing brain tumor in children strongly needs to be addressed.
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Affiliation(s)
- Elvis Terci Valera
- Department of Pediatrics, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil.
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8
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Dahlback HSS, Brandal P, Gorunova L, Widing E, Meling TR, Krossnes BK, Heim S. Genomic aberrations in pediatric gliomas and embryonal tumors. Genes Chromosomes Cancer 2011; 50:788-99. [DOI: 10.1002/gcc.20898] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Revised: 04/29/2011] [Accepted: 05/11/2011] [Indexed: 12/15/2022] Open
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Anagnostopoulos AK, Dimas KS, Papathanassiou C, Braoudaki M, Anastasiadou E, Vougas K, Karamolegou K, Kontos H, Prodromou N, Tzortzatou-Stathopoulou F, Tsangaris GT. Proteomics Studies of Childhood Pilocytic Astrocytoma. J Proteome Res 2011; 10:2555-65. [DOI: 10.1021/pr200024m] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Athanasios K. Anagnostopoulos
- Proteomics Research Unit, Center of Basic Research II, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
- Hematology/Oncology Unit, First Department of Pediatrics, University of Athens, Aghia Sophia Children’s Hospital, Athens, Greece
| | - Konstantinos S. Dimas
- Pharmacology Division, Center of Basic Research I, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
| | - Chrissa Papathanassiou
- Hematology/Oncology Unit, First Department of Pediatrics, University of Athens, Aghia Sophia Children’s Hospital, Athens, Greece
| | - Maria Braoudaki
- Hematology/Oncology Unit, First Department of Pediatrics, University of Athens, Aghia Sophia Children’s Hospital, Athens, Greece
- University Research Institute for the Study and Treatment of Childhood Genetic and Malignant Diseases, University of Athens, Aghia Sophia Children’s Hospital, Athens, Greece
| | - Ema Anastasiadou
- Proteomics Research Unit, Center of Basic Research II, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
| | - Konstantinos Vougas
- Proteomics Research Unit, Center of Basic Research II, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
| | - Kalliopi Karamolegou
- Hematology/Oncology Unit, First Department of Pediatrics, University of Athens, Aghia Sophia Children’s Hospital, Athens, Greece
| | - Harry Kontos
- “Genomedica” Molecular Diagnostics Laboratory, Piraeus, Greece
| | - Neofytos Prodromou
- Department of Neurosurgery, Aghia Sophia Children’s Hospital, Athens, Greece
| | - Fotini Tzortzatou-Stathopoulou
- University Research Institute for the Study and Treatment of Childhood Genetic and Malignant Diseases, University of Athens, Aghia Sophia Children’s Hospital, Athens, Greece
| | - George Th. Tsangaris
- Proteomics Research Unit, Center of Basic Research II, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
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Ward SJ, Karakoula K, Phipps KP, Harkness W, Hayward R, Thompson D, Jacques TS, Harding B, Darling JL, Thomas DGT, Warr TJ. Cytogenetic analysis of paediatric astrocytoma using comparative genomic hybridisation and fluorescence in-situ hybridisation. J Neurooncol 2010; 98:305-18. [DOI: 10.1007/s11060-009-0081-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2009] [Accepted: 11/30/2009] [Indexed: 11/29/2022]
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Abstract
Pediatric low-grade gliomas encompass a heterogeneous set of tumors of different histologies. Cerebellar pilocytic astrocytomas occur most frequently followed by supratentorial diffuse fibrillary astrocytomas. Recent research has implicated activation of the RAS/RAF/MEK pathway in tumorigenesis of these tumors. Surgery is the mainstay of therapy. Overall survival rates for patients whose tumors are completely resected are 90% or greater, 10 years from diagnosis. Conversely, most optic pathway/hypothalamic, deep midline, and brain stem gliomas have minimal potential for resection; these tumors can be difficult to treat and deserve special attention. Combination chemotherapy is currently recommended as front-line adjuvant treatment for progressive or recurrent tumors. Second-line radiotherapy can also improve overall survival but is associated with more frequent and significant neurocognitive, endocrine, and other long-term toxicities.
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Affiliation(s)
- Angela J Sievert
- Division of Oncology, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
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Hamlat A, Saikali S, Diabira S, Messerer M, Riffaud L. Diagnosis of childhood astrocytomas. EXPERT OPINION ON MEDICAL DIAGNOSTICS 2009; 3:501-522. [PMID: 23495981 DOI: 10.1517/17530050903032679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
BACKGROUND Astrocytomas are the most common brain tumours, accounting for 28 - 50% of all primary CNS tumours. Diagnosis of CNS tumours remains difficult because the varied and nonspecific presentations of CNS tumours in childhood. Objectives/method: The clinical presentations of CNS astrocytomas vary with their sites of location; therefore, a period of uncertainty often precedes diagnosis, and approximately 42% of patients with an intracranial process make several visits to various physicians between the onset and diagnosis. However, on clinical suspicion of a brain tumour, a wide range of neuroimaging techniques may be used to assess the diagnosis of paediatric brain lesions. In this review the authors, for ease of presentation, describe the clinical presentations of supratentorial, infratentorial and spinal cord astrocytomas as well as their radiological and pathological features, and discuss their differential diagnoses. RESULTS/CONCLUSIONS Understanding and mastering the numerous imaging features of several subtypes of primary brain tumours affecting children, in addition to radiological features of non-tumoural disorders, remains a significant challenge and demands increased awareness of the paediatric brain diseases.
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Affiliation(s)
- Abderrahmane Hamlat
- Department of Neurosurgery, CHU Pontchaillou, 2 Rue Henri Le Guilloux, 35000 Rennes Cedex 2, France +33 2 99 28 43 21 ; +33 2 99 28 41 80 ;
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Low-grade astrocytoma in a child with encephalocraniocutaneous lipomatosis. J Neurooncol 2009; 96:437-41. [PMID: 19652916 DOI: 10.1007/s11060-009-9978-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2009] [Accepted: 07/13/2009] [Indexed: 10/20/2022]
Abstract
Encephalocutaneous lipomatosis (ECCL), or Haberland syndrome, is an uncommon congenital disorder with unique cutaneous, ocular and neurological features. In the present article, we describe a 3-year-old boy with ECCL who developed an extensive and recurring intraventricular low-grade glioma with atypical pathological features and elevated mitotic index. Cytogenetic analysis from tumor sample was also performed. This is the first report of a low-grade astrocytoma occurring in a child with ECCL. Whether or not the origin of the tumor is associated to the pathogenesis of the underlying syndrome is a matter for further investigation.
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Mueller S, Chang S. Pediatric brain tumors: current treatment strategies and future therapeutic approaches. Neurotherapeutics 2009; 6:570-86. [PMID: 19560746 PMCID: PMC5084192 DOI: 10.1016/j.nurt.2009.04.006] [Citation(s) in RCA: 127] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2009] [Revised: 04/11/2009] [Accepted: 04/13/2009] [Indexed: 01/19/2023] Open
Abstract
Pediatric CNS tumors are the most common solid tumors of childhood and the second most common cancer after hematological malignancies accounting for approximate 20 to 25% of all primary pediatric tumors. With over 3,000 new cases per year in the United States, childhood CNS tumors are the leading cause of death related to cancer in this population. The prognosis for these patients has improved over the last few decades, but current therapies continue to carry a high risk of significant side effects, especially for the very young. Currently a combination of surgery, radiation, and chemotherapy is often used in children greater than 3 years of age. This article will outline current and future therapeutic strategies for the most common pediatric CNS tumors, including primitive neuroectodermal tumors such as medulloblastoma, as well as astrocytomas and ependymomas.
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Affiliation(s)
- Sabine Mueller
- Department of Neurology, Division of Child Neurology, University of San Francisco, San Francisco, California, USA.
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Abstract
Pediatric gliomas comprise a clinically, histologically, and molecularly very heterogeneous group of CNS tumors. In addition, these tumors are largely different from their counterparts occurring in adults, although they are histologically indistinguishable and uniformly classified by the current WHO classification for CNS tumors. Pilocytic astrocytoma (WHO grade I), mainly arising in the posterior fossa, is the most common representative in children, whereas glioblastoma multiforme (WHO grade IV) predominates in adults. When radical surgical resection is possible in low-grade gliomas, it will likely cure the patient. If complete surgical resection is not possible, however, for example in brainstem gliomas, which are defined by their anatomic localization rather than by their histological or molecular features, therapeutic options are limited and prognosis is usually poor. Recent genome-wide analyses applying different microarray-based methods to investigate DNA copy-number aberrations, mRNA expression signatures, and methylation patterns have shed some light on the pathways involved in the pathogenesis of pediatric glio-mas. Mitogen-activated protein kinase (MAPK) and PI3K/AKT signaling were identified as prominent oncogenic pathways in astrocytic tumors in several studies, whereas NOTCH signaling was implicated in the pathogenesis of a subset of intracranial ependymomas. Future therapeutic strategies targeting these (and other) pathways or conferring epigenetic modifications in the tumor might contribute to a better treatment outcome of patients with unresectable or disseminated tumors at diagnosis. Consideration of reliable molecular markers for outcome prediction will most likely result in a better stratification of patients into different risk groups with adjusted treatment intensity in the future.
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Pfister S, Janzarik WG, Remke M, Ernst A, Werft W, Becker N, Toedt G, Wittmann A, Kratz C, Olbrich H, Ahmadi R, Thieme B, Joos S, Radlwimmer B, Kulozik A, Pietsch T, Herold-Mende C, Gnekow A, Reifenberger G, Korshunov A, Scheurlen W, Omran H, Lichter P. BRAF gene duplication constitutes a mechanism of MAPK pathway activation in low-grade astrocytomas. J Clin Invest 2008; 118:1739-49. [PMID: 18398503 DOI: 10.1172/jci33656] [Citation(s) in RCA: 360] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2007] [Accepted: 02/13/2008] [Indexed: 12/30/2022] Open
Abstract
The molecular pathogenesis of pediatric astrocytomas is still poorly understood. To further understand the genetic abnormalities associated with these tumors, we performed a genome-wide analysis of DNA copy number aberrations in pediatric low-grade astrocytomas by using array-based comparative genomic hybridization. Duplication of the BRAF protooncogene was the most frequent genomic aberration, and tumors with BRAF duplication showed significantly increased mRNA levels of BRAF and a downstream target, CCND1, as compared with tumors without duplication. Furthermore, denaturing HPLC showed that activating BRAF mutations were detected in some of the tumors without BRAF duplication. Similarly, a marked proportion of low-grade astrocytomas from adult patients also had BRAF duplication. Both the stable silencing of BRAF through shRNA lentiviral transduction and pharmacological inhibition of MEK1/2, the immediate downstream phosphorylation target of BRAF, blocked the proliferation and arrested the growth of cultured tumor cells derived from low-grade gliomas. Our findings implicate aberrant activation of the MAPK pathway due to gene duplication or mutation of BRAF as a molecular mechanism of pathogenesis in low-grade astrocytomas and suggest inhibition of the MAPK pathway as a potential treatment.
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Affiliation(s)
- Stefan Pfister
- Division Molecular Genetics, German Cancer Research Center (DKFZ), Heidelberg, Germany
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Faury D, Nantel A, Dunn SE, Guiot MC, Haque T, Hauser P, Garami M, Bognár L, Hanzély Z, Liberski PP, Lopez-Aguilar E, Valera ET, Tone LG, Carret AS, Del Maestro RF, Gleave M, Montes JL, Pietsch T, Albrecht S, Jabado N. Molecular Profiling Identifies Prognostic Subgroups of Pediatric Glioblastoma and Shows Increased YB-1 Expression in Tumors. J Clin Oncol 2007; 25:1196-208. [PMID: 17401009 DOI: 10.1200/jco.2006.07.8626] [Citation(s) in RCA: 173] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Purpose Pediatric glioblastoma (pGBM) is a rare, but devastating brain tumor. In contrast to GBM in adults (aGBM), little is known about the mechanisms underlying its development. Our aim is to gain insight into the molecular pathways of pGBM. Materials and Methods Thirty-two pGBM and seven aGBM samples were investigated using biochemical and transcriptional profiling. Ras and Akt pathway activation was assessed through the phosphorylation of downstream effectors, and gene expression profiles were generated using the University Health Network Human 19K cDNA arrays. Results were validated using real-time polymerase chain reaction and immunohistochemistry and compared with existing data sets on aGBM. Results There are at least two subsets of pGBM. One subset, associated with Ras and Akt pathway activation, has very poor prognosis and exhibits increased expression of genes related to proliferation and to a neural stem-cell phenotype, similar to findings in aggressive aGBM. This subset was still molecularly distinguishable from aGBM after unsupervised and supervised analysis of expression profiles. A second subset, with better prognosis, is not associated with activation of Akt and Ras pathways, may originate from astroglial progenitors, and does not express gene signatures and markers shown to be associated with long-term survival in aGBM. Both subsets of pGBM show overexpression of Y-box-protein-1 that may help drive oncogenesis in this tumor. Conclusion Our work, the first study of gene expression profiles in pGBM, provides valuable insight into active pathways and targets in a cancer with minimal survival, and suggests that these tumors cannot be understood exclusively through studies of aGBM.
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Affiliation(s)
- Damien Faury
- Division of Hemato-Oncology, Department of Pediatrics, Montréal Children's Hospital Research Institute, Montréal, Quebec, Canada
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Foreman NK, Gore L, Wells D, Straessle J, Heideman R, Donson AM. Gefitinib is effective against juvenile pilocytic astrocytoma in vitro. Pediatr Blood Cancer 2006; 47:293-8. [PMID: 16206208 DOI: 10.1002/pbc.20619] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
BACKGROUND Juvenile pilocytic astrocytomas (JPAs) are the most common central nervous system tumors in children. If completely resected, JPAs are associated with an excellent outcome. However, there is need for additional therapeutic approaches for those JPAs which are incompletely resected and fail subsequent standard chemotherapy/radiation. To explore the possibility for a novel therapeutic approach we measured the effect of the epidermal growth factor receptor (EGFR) small molecule tyrosine kinase inhibitor gefitinib on five JPA primary cell-cultures. PROCEDURE Due to a lack of established cell-lines of JPA very few in vitro drug sensitivity assays have been performed. In this study we have succeeded in propagating short-term primary cell-cultures established from surgical specimens. The effect of gefitinib on proliferation in JPA derived primary cell-cultures was measured by a standard tritiated thymidine incorporation assay. The level of expression of EGFR, the intended target of gefitinib, was measured by immunohistochemistry, flow cytometry and RT-PCR. RESULTS Gefitinib was shown to inhibit proliferation in all five JPA cell-cultures tested, with IC-50's between 1.6 and 9.6 microM. However, EGFR protein and mRNA expression was undetectable. Further studies with cetuximab, an EGFR-specific inhibitory monoclonal antibody, showed no effect on proliferation in JPA. CONCLUSIONS Based on these preclinical data, gefitinib may be a suitable salvage chemotherapy drug to explore further in those patients with JPA who have recurred after primary chemotherapy. Of interest, it appears that the anti-tumor effect of gefitinib in JPA cell-cultures may be mediated through a pathway other than EGFR inhibition.
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Affiliation(s)
- Nicholas K Foreman
- University of Colorado at Denver and Health Sciences Center (UCDHSC) and The Children's Hospital, Denver, Colorado.
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Bayani J, Pandita A, Squire JA. Molecular cytogenetic analysis in the study of brain tumors: findings and applications. Neurosurg Focus 2005; 19:E1. [PMID: 16398459 DOI: 10.3171/foc.2005.19.5.2] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Classic cytogenetics has evolved from black and white to technicolor images of chromosomes as a result of advances in fluorescence in situ hybridization (FISH) techniques, and is now called molecular cytogenetics. Improvements in the quality and diversity of probes suitable for FISH, coupled with advances in computerized image analysis, now permit the genome or tissue of interest to be analyzed in detail on a glass slide. It is evident that the growing list of options for cytogenetic analysis has improved the understanding of chromosomal changes in disease initiation, progression, and response to treatment. The contributions of classic and molecular cytogenetics to the study of brain tumors have provided scientists and clinicians alike with new avenues for investigation. In this review the authors summarize the contributions of molecular cytogenetics to the study of brain tumors, encompassing the findings of classic cytogenetics, interphase- and metaphase-based FISH studies, spectral karyotyping, and metaphase- and array-based comparative genomic hybridization. In addition, this review also details the role of molecular cytogenetic techniques in other aspects of understanding the pathogenesis of brain tumors, including xenograft, cancer stem cell, and telomere length studies.
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Affiliation(s)
- Jane Bayani
- Department of Applied Molecular Oncology, Ontario Cancer Institute, Princess Margaret Hospital, University Health Network, Ontario, Canada.
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Rickert CH, Paulus W. Prognosis-related histomorphological and immunohistochemical markers in central nervous system tumors of childhood and adolescence. Acta Neuropathol 2005; 109:69-92. [PMID: 15647946 DOI: 10.1007/s00401-004-0959-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2004] [Accepted: 10/11/2004] [Indexed: 10/26/2022]
Abstract
Brain tumors account for approximately 20% of all childhood cancers, and are the leading cause of cancer morbidity and mortality among children. Although numerous demographic, clinical and therapeutic parameters have been identified over the past few years that have significant prognostic bearing for some pediatric brain tumors, predicting the clinical course and outcome among children with central nervous system tumors is still difficult. A survey of publications on prognosis-related histopathological and immunohistochemical features among pediatric brain tumors revealed 172 series, of which 91 presented statistically significant outcome-associated parameters as defined by a P value of less than 0.05. Most investigations revealing significant prognosis-related markers were performed on medulloblastomas (30 publications), ependymomas (25) and astrocytic tumors (18). In total, 16 cohorts consisted of more than 100 cases (5 on ependymomas, 3 each on medulloblastomas and astrocytic tumors). On the other hand, there were also 13 series with fewer than 20 cases (5 on medulloblastomas). Potentially prognostic histopathological markers vary among different entities and consist of assessment of necroses, mitoses, differentiation, vascular proliferation, and growth pattern, whereas immunohistochemical features include proliferation markers (Ki-67, MIB-1), expression of oncogenes/tumor suppressor genes and their proteins (TP53, c-erbB2), growth factor and hormonal receptors (VEGF, EGFR, HER2, HER4, ErbB-2), cell cycle genes (p27, p14ARF) and cell adhesion molecules, as well as factors potentially related to therapeutic resistance (DNA topoisomerase IIalpha, metallothionein, P-glycoprotein, tenascin). This review discusses the prognostic potential of histopathological and immunohistochemical markers that can be investigated by the practicing neuropathologist as part of the routine diagnostic workload, and scrutinizes their benefit for predicting therapy response and patient outcome among children with brain tumors.
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