Project description:Glioblastoma (GBM) is an incurable brain tumor carrying a dismal prognosis, which displays considerable heterogeneity. We have recently identified recurrent H3F3A mutations affecting two critical positions of histone H3.3 (K27, G34) in one-third of pediatric GBM. Here we show that each of these H3F3A mutations defines an epigenetic subgroup of GBM with a distinct global methylation pattern, and are mutually exclusive with IDH1 mutation (characterizing a CpG-Island Methylator Phenotype (CIMP) subgroup). Three further epigenetic subgroups were enriched for hallmark genetic events of adult GBM (EGFR amplification, CDKN2A/B deletion) and/or known transcriptomic signatures. We also demonstrate that the two H3F3A mutations give rise to GBMs in separate anatomic compartments, with differential regulation of OLIG1/2 and FOXG1, possibly reflecting different cellular origins. To further dissect the biological differences between epigenetic glioblastoma subgroups, we looked at the transcriptomic profiles of glioblastoma samples. 46 glioblastoma samples from patients of various ages were selected for RNA extraction and hybridization on Affymetrix Affymetrix Human Genome U133 Plus 2.0 Arrays.
Project description:Glioblastoma (GBM) is an incurable brain tumor carrying a dismal prognosis, which displays considerable heterogeneity. We have recently identified recurrent H3F3A mutations affecting two critical positions of histone H3.3 (K27, G34) in one-third of pediatric GBM. Here we show that each of these H3F3A mutations defines an epigenetic subgroup of GBM with a distinct global methylation pattern, and are mutually exclusive with IDH1 mutation (characterizing a CpG-Island Methylator Phenotype (CIMP) subgroup). Three further epigenetic subgroups were enriched for hallmark genetic events of adult GBM (EGFR amplification, CDKN2A/B deletion) and/or known transcriptomic signatures. We also demonstrate that the two H3F3A mutations give rise to GBMs in separate anatomic compartments, with differential regulation of OLIG1/2 and FOXG1, possibly reflecting different cellular origins. To further dissect the biological differences between epigenetic glioblastoma subgroups, we looked at the transcriptomic profiles of glioblastoma samples.
Project description:Glioblastoma (GBM) is an incurable brain tumor carrying a dismal prognosis, which displays considerable heterogeneity. We have recently identified recurrent H3F3A mutations affecting two critical positions of histone H3.3 (K27, G34) in one-third of pediatric GBM. Here we show that each of these H3F3A mutations defines an epigenetic subgroup of GBM with a distinct global methylation pattern, and are mutually exclusive with IDH1 mutations (characterizing a CpG-Island Methylator Phenotype (CIMP) subgroup). Three further epigenetic subgroups were enriched for hallmark genetic events of adult GBM (EGFR amplification, CDKN2A/B deletion) and/or known transcriptomic signatures. We also demonstrate that the two H3F3A mutations give rise to GBMs in separate anatomic compartments, with differential regulation of OLIG1/2 and FOXG1, possibly reflecting different cellular origins. We identified six epigenetic and biological GBM subgroups displaying distinct global DNA methylation patterns, which harbor unique hotspot mutations, DNA copy-number alterations, and transcriptomic patterns. We investigated a subset of childhood (n=59) and adult GBMs (n=77) using the Illumina 450k methylation array. Six non-neoplastic brain tissue samples are included as controls.
Project description:Glioblastoma (GBM) is an incurable brain tumor carrying a dismal prognosis, which displays considerable heterogeneity. We have recently identified recurrent H3F3A mutations affecting two critical positions of histone H3.3 (K27, G34) in one-third of pediatric GBM. Here we show that each of these H3F3A mutations defines an epigenetic subgroup of GBM with a distinct global methylation pattern, and are mutually exclusive with IDH1 mutations (characterizing a CpG-Island Methylator Phenotype (CIMP) subgroup). Three further epigenetic subgroups were enriched for hallmark genetic events of adult GBM (EGFR amplification, CDKN2A/B deletion) and/or known transcriptomic signatures. We also demonstrate that the two H3F3A mutations give rise to GBMs in separate anatomic compartments, with differential regulation of OLIG1/2 and FOXG1, possibly reflecting different cellular origins. We identified six epigenetic and biological GBM subgroups displaying distinct global DNA methylation patterns, which harbor unique hotspot mutations, DNA copy-number alterations, and transcriptomic patterns.
Project description:Ependymoma (EPN) is the third most common central nervous system (CNS) tumor in childhood and, recently, has been classified in nine robust molecular subgroups (Pajtler et al., 2015). However, molecular and clinical features of pediatric EPNs from Brazilian cohorts remain unexplored. Herein, we aimed to analyze the gene expression profile among three different molecular subgroups: ST-EPN-RELA, ST-EPN-YAP1 and PF-EPN-A.
Project description:Pediatric high-grade gliomas (pHGGs) harboring the K27M mutation of H3F3A (histone H3.3) are characterized by global reduction of the repressive histone mark H3K27me3 and DNA hypomethylation. Analysis of K27M-induced changes on H3K27me3 occupancy and DNA methylation at differentially expresed genes (K27M vs. wild-type H3.3) in primary pHGG tumor samples. 22 glioblastoma samples from pHGG patients were selected for RNA extraction and hybridization on Affymetrix Affymetrix Human Genome U133 Plus 2.0 Arrays. Expression profiling data of 17 pHHGs are part of our previous study (GSE36245 or GSE34824).
Project description:Glioblastoma (GBM) is an incurable brain tumor carrying a dismal prognosis, which displays considerable heterogeneity. We have recently identified recurrent H3F3A mutations affecting two critical positions of histone H3.3 (K27, G34) in one-third of pediatric GBM. Here we show that each of these H3F3A mutations defines an epigenetic subgroup of GBM with a distinct global methylation pattern, and are mutually exclusive with IDH1 mutation (characterizing a CpG-Island Methylator Phenotype (CIMP) subgroup). Three further epigenetic subgroups were enriched for hallmark genetic events of adult GBM (EGFR amplification, CDKN2A/B deletion) and/or known transcriptomic signatures. We also demonstrate that the two H3F3A mutations give rise to GBMs in separate anatomic compartments, with differential regulation of OLIG1/2 and FOXG1, possibly reflecting different cellular origins. To further dissect the biological differences between epigenetic glioblastoma subgroups, we looked at the transcriptomic profiles of glioblastoma samples. 46 glioblastoma samples from patients of various ages were selected for RNA extraction and hybridization on Affymetrix Affymetrix Human Genome U133 Plus 2.0 Arrays.
Project description:Glioblastoma (GBM) is the most common and aggressive primary central nervous system malignancy, with median survival of 15 months. Glioblastoma represents extraordinarily high tumor heterogeneity and alterations in genomic, transcriptomic or methylomic levels. To gain deeper insights into the molecular processes involved we studied transcriptome wide expression profiles using RNAseq of normal/tumor tissue pairs of 12 GBM patients and systematically analyzed the differentially expressed genes.