title: Mesenchymal transition and PDGFRA amplification/mutation are key distinct oncogenic events in pediatric diffuse intrinsic pontine gliomas.
abstract: Diffuse intrinsic pontine glioma (DIPG) is one of the most frequent malignant pediatric brain tumor and its prognosis is universaly fatal. No significant improvement has been made in last thirty years over the standard treatment with radiotherapy. To address the paucity of understanding of DIPGs, we have carried out integrated molecular profiling of a large series of samples obtained with stereotactic biopsy at diagnosis. While chromosomal imbalances did not distinguish DIPG and supratentorial tumors on CGHarrays, gene expression profiling revealed clear differences between them, with brainstem gliomas resembling midline/thalamic tumours, indicating a closely-related origin. Two distinct subgroups of DIPG were identified. The first subgroup displayed mesenchymal and pro-angiogenic characteristics, with stem cell markers enrichment consistent with the possibility to grow tumor stem cells from these biopsies. The other subgroup displayed oligodendroglial features, and appeared largely driven by PDGFRA, in particular through amplification and/or novel missense mutations in the extracellular domain. Patients in this later group had a significantly worse outcome with an hazard ratio for early deaths, ie before 10 months, 8 fold greater that the ones in the other subgroup (p = 0.041, Cox regression model). The worse outcome of patients with the oligodendroglial type of tumors was confirmed on a series of 55 paraffin-embedded biopsy samples at diagnosis (median OS of 7.73 versus 12.37 months, p = 0.045, log-rank test). Two distinct transcriptional subclasses of DIPG with specific genomic alterations can be defined at diagnosis by oligodendroglial differentiation or mesenchymal transition, respectively. Classifying these tumors by signal transduction pathway activation and by mutation in pathway member genes may be particularily valuable for the development of targeted therapies.
authors.affiliation: Department of Neurosurgery, Necker-Sick Children Hospital, University Paris V Descartes, Paris, France.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Puget
authors.forename: Cathy
authors.initials: C
authors.lastname: Philippe
authors.forename: Dorine A
authors.initials: DA
authors.lastname: Bax
authors.forename: Bastien
authors.initials: B
authors.lastname: Job
authors.forename: Pascale
authors.initials: P
authors.lastname: Varlet
authors.forename: Marie-Pierre
authors.initials: MP
authors.lastname: Junier
authors.forename: Felipe
authors.initials: F
authors.lastname: Andreiuolo
authors.forename: Dina
authors.initials: D
authors.lastname: Carvalho
authors.forename: Ricardo
authors.initials: R
authors.lastname: Reis
authors.forename: Lea
authors.initials: L
authors.lastname: Guerrini-Rousseau
authors.forename: Thomas
authors.initials: T
authors.lastname: Roujeau
authors.forename: Philippe
authors.initials: P
authors.lastname: Dessen
authors.forename: Catherine
authors.initials: C
authors.lastname: Richon
authors.forename: Vladimir
authors.initials: V
authors.lastname: Lazar
authors.forename: Gwenael
authors.initials: G
authors.lastname: Le Teuff
authors.forename: Christian
authors.initials: C
authors.lastname: Sainte-Rose
authors.forename: Birgit
authors.initials: B
authors.lastname: Geoerger
authors.forename: Gilles
authors.initials: G
authors.lastname: Vassal
authors.forename: Chris
authors.initials: C
authors.lastname: Jones
authors.forename: Jacques
authors.initials: J
authors.lastname: Grill
mesh_terms: D020295:Brain Stem Neoplasms / Q000235:genetics* / Q000378:metabolism* / Q000473:pathology; D058750:Epithelial-Mesenchymal Transition / Q000235:genetics*; D020869:Gene Expression Profiling / Q000379:methods*; D006801:Humans; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D009154:Mutation; D020796:Receptor, Platelet-Derived Growth Factor alpha / Q000235:genetics* / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics; D000071250:Snail Family Transcription Factors; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D000071250:Snail Family Transcription Factors; D014157:Transcription Factors; D020796:Receptor, Platelet-Derived Growth Factor alpha