Project description:miRNA expression analysis was performed on 14 cases of high grade gliomas and 4 controls obtained from age-matched epileptic patients. After this differentially miRNA analysis has been done among T53,H3F3A,normal and pediatric high grade glioma patient and try to identify the highly altered miRNA expression as well as sno expression pattern.
Project description:The outcome for children with high-grade gliomas (HGG) remains dismal, with a two-year survival rate of only 10-30%. Approximately half of pediatric HGGs are diffuse intrinsic pontine glioma (DIPG), a brainstem tumor that arises almost exclusively in children. Genome-wide analyses of copy number imbalances previously showed that platelet derived growth factor receptor alpha (PDGFRA) is the most frequent target of focal amplification in pediatric HGGs. To determine whether the PDGFRA is also targeted by more subtle mutations not detected by copy number analysis, we sequenced all PDGFRA coding exons from a cohort of pediatric HGGs. Somatic activating mutations were identified in 14.4% (13/90) of non-brainstem pediatric HGGs and 4.7% (2/43) of DIPGs, including missense mutations and in-frame deletions and insertions not previously described. 40% of tumors with mutation showed concurrent amplification, while 60% carried heterozygous mutations. Six different mutations impacting different domains all resulted in ligand-independent receptor activation that was blocked by small molecule inhibitors of PDGFR. Expression of mutants in p53-null primary mouse astrocytes conferred a proliferative advantage in vitro, and generated HGGs in vivo with complete penetrance when implanted into brain. The gene expression signatures reflected the spectrum of human diffuse HGGs. PDGFRA intragenic deletion of exons 8 and 9 were previously shown in adult HGG, but were not detected in 83 non-brainstem pediatric HGG and 57 DIPGs. Thus, a distinct spectrum of mutations confers constitutive receptor activation and oncogenic activity to PDGFR in childhood HGG. To better understand the consequence of PDGFRα mutation in pediatric gliomagenesis, retroviral constructs expressing wild-type PDGFRα or six selected PDGFRα mutants that affect different regions of the receptor were generated for functional studies. p53-null primary mouse astrocyte (PMA) cultures were chosen as a relevant cellular background to assess PDGFRα function.
Project description:Purpose: To define copy number alterations and gene expression signatures underlying pediatric high-grade glioma (HGG). Patients and Methods: We conducted a high-resolution analysis of genomic imbalances in 78 de novo pediatric HGG, including 7 diffuse intrinsic pontine gliomas, and 10 HGG cases arising in children who received cranial irradiation for a previous cancer, using Affymetrix 500K GeneChips. Gene expression signatures for 53 tumors were analyzed with Affymetrix U133v2 arrays. Results were compared with publicly available data from adult tumors. Results: Pediatric and adult glioblastoma were clearly distinguished by frequent gain of chromosome 1q (30% vs 9%) and lower frequency of chromosome 7 gain (13% vs 74%), respectively. The most common focal amplifications also differed, with PDGFRA and EGFR predominant in childhood and adult populations respectively. These common alterations in pediatric HGG were detected at higher frequency in irradiation-induced tumors, suggesting that these are initiating events in childhood gliomagenesis. CDKN2A was the most common tumor suppressor gene targeted by homozygous deletion in pediatric HGG. No IDH1 hotspot mutations were found in pediatric tumors, highlighting molecular differences in pathogenesis between childhood HGG and adult secondary glioblastoma. Integrated copy number and gene expression data indicated that deregulated PDGFRA signaling plays a major role in pediatric HGG. Conclusions: Integrated molecular profiling showed substantial differences in the molecular features underlying pediatric and adult HGG, indicating that findings in adult tumors cannot be simply extrapolated to younger patients. PDGFRA may be a useful target for pediatric HGG including diffuse pontine gliomas. Keywords: disease state analysis 78 samples for SNP analysis, including 10 samples arising in children who received cranial irradiation for a previous cancer and 7 diffuse pontine gliomas; 53 of them with gene expression analysis; 2 tumor grades To have access to SNP CEL files, please contact Dr. Suzanne Baker (suzzane.baker@stjude.org).
Project description:The outcome for children with high-grade gliomas (HGG) remains dismal, with a two-year survival rate of only 10-30%. Approximately half of pediatric HGGs are diffuse intrinsic pontine glioma (DIPG), a brainstem tumor that arises almost exclusively in children. Genome-wide analyses of copy number imbalances previously showed that platelet derived growth factor receptor alpha (PDGFRA) is the most frequent target of focal amplification in pediatric HGGs. To determine whether the PDGFRA is also targeted by more subtle mutations not detected by copy number analysis, we sequenced all PDGFRA coding exons from a cohort of pediatric HGGs. Somatic activating mutations were identified in 14.4% (13/90) of non-brainstem pediatric HGGs and 4.7% (2/43) of DIPGs, including missense mutations and in-frame deletions and insertions not previously described. 40% of tumors with mutation showed concurrent amplification, while 60% carried heterozygous mutations. Six different mutations impacting different domains all resulted in ligand-independent receptor activation that was blocked by small molecule inhibitors of PDGFR. Expression of mutants in p53-null primary mouse astrocytes conferred a proliferative advantage in vitro, and generated HGGs in vivo with complete penetrance when implanted into brain. The gene expression signatures reflected the spectrum of human diffuse HGGs. PDGFRA intragenic deletion of exons 8 and 9 were previously shown in adult HGG, but were not detected in 83 non-brainstem pediatric HGG and 57 DIPGs. Thus, a distinct spectrum of mutations confers constitutive receptor activation and oncogenic activity to PDGFR in childhood HGG.
Project description:Purpose: To define copy number alterations and gene expression signatures underlying pediatric high-grade glioma (HGG). Patients and Methods: We conducted a high-resolution analysis of genomic imbalances in 78 de novo pediatric HGG, including 7 diffuse intrinsic pontine gliomas, and 10 HGG cases arising in children who received cranial irradiation for a previous cancer, using Affymetrix 500K GeneChips. Gene expression signatures for 53 tumors were analyzed with Affymetrix U133v2 arrays. Results were compared with publicly available data from adult tumors. Results: Pediatric and adult glioblastoma were clearly distinguished by frequent gain of chromosome 1q (30% vs 9%) and lower frequency of chromosome 7 gain (13% vs 74%), respectively. The most common focal amplifications also differed, with PDGFRA and EGFR predominant in childhood and adult populations respectively. These common alterations in pediatric HGG were detected at higher frequency in irradiation-induced tumors, suggesting that these are initiating events in childhood gliomagenesis. CDKN2A was the most common tumor suppressor gene targeted by homozygous deletion in pediatric HGG. No IDH1 hotspot mutations were found in pediatric tumors, highlighting molecular differences in pathogenesis between childhood HGG and adult secondary glioblastoma. Integrated copy number and gene expression data indicated that deregulated PDGFRA signaling plays a major role in pediatric HGG. Conclusions: Integrated molecular profiling showed substantial differences in the molecular features underlying pediatric and adult HGG, indicating that findings in adult tumors cannot be simply extrapolated to younger patients. PDGFRA may be a useful target for pediatric HGG including diffuse pontine gliomas. Keywords: disease state analysis
Project description:We performed gene expression profiling on 151 paraffin-embedded PLGGs from different locations, ages, histological subtypes as well as BRAF genetic status We also compared molecular differences to normal pediatric brain expression profiles to observe whether those patterns were mirrored in normal brain expression. We analyzed the expression of 6,100 genes among 151 FFPE pediatric and 15 FFPE adult low-grade gliomas and analyzed how the expression patterns changes with location, age, histology and BRAF genomic status and how those differences were mirrored in normal brain expression. The values in the sample 'characteristics' columns represent; Location; SUP= Supratentorial, INF= Infratentorial Histology; PA= pilocytic astrocytoma, GG= ganglioglioma, DNT= dysembryoplastic neuroepithelial tumor, OD= oligodendroglial tumors, NOS= not otherwise specified tumors BRAF status; DUP= BRAF duplication, MUT= BRAF V600E mutation, WT= wild type, ND= not determined Primary or recurrent tumor; P=primary, R=recurrent Primary tumor that further progressed; 1=yes, 0=no, _=recurrent tumors only
Project description:Pediatric high-grade gliomas (pHGGs), including glioblastoma multiforme (GBM) and diffuse intrinsic pontine glioma (DIPG), are highly morbid childhood brain tumors. Even with treatment, overall survival is poor, making pHGG the number one cause of cancer death in children. Up to 80% of DIPGs harbor a somatic missense mutation in genes encoding Histone H3 proteins. To investigate whether this H3K27M mutation is associated with distinct chromatin structure that alters transcription regulation, we generated the first high-resolution Hi-C maps of pHGG cell lines and tumor tissue. By integrating transcriptome (RNA-Seq), enhancer landscape (ChIP-Seq), genome structure (Hi-C), and chromatin accessibility (ATAC-Seq) datasets from H3K27M mutant and wild-type specimens, we identified tumor specific enhancers and regulatory networks for known oncogenes. In addition, we identified distinct genomic structural variations that lead to enhancer hijacking and gene co-amplification, including A2M, JAG2, FLRT1.
Project description:We carried out the analyses of chromosome variations between low-grade and high-grade gliomas in Chinese population. We found out the differences in chromosomes, cytobands, genes, pathways and GO functions. To identify the glioma tissue-specific genomic alterations and compare the genomic variations between low-grade and high-grade gliomas.