Project description:Genome-wide DNA methylation profiling of 32 NF1-associated gliomas. The Illumina Infinium EPIC 850k Human DNA Methylation Beadchip was used to obtain DNA methylation profiles across approximately 850,000 CpG sites of genomic DNA extracted from formalin-fixed, paraffin-embedded tumor tissue of 32 gliomas.
Project description:As genome-scale technologies begin to unravel the complexity of the equivalent tumours in adults, detailed characterisation of high grade gliomas in children have until recently been lacking. In order to validate and extend investigations of the differences between paediatric and adult tumours, we carried out copy number profiling by array CGH using a 32K BAC platform on 63 formalin-fixed paraffin-embedded (FFPE) cases of high grade glioma arising in children and young people (<23 yrs).
Project description:Gliomas arising in the brainstem and thalamus are devastating tumors that are difficult to surgically resect due to their proximity to eloquent brain structures. Here, we performed a comprehesive genomic and epigenomic study, using gene expression and methylation microarrays, to research on th different genomic and epigenetic signatures between brainstem, thalamic, and supratentorial gliomas. Comparison of brainstem, thalamic and supratentorial gliomas
Project description:Purpose: More than 90% of children with diffuse intrinsic pontine glioma (DIPG) die within 2 years of diagnosis. There is a dire need to identify therapeutic targets, however lack of patient material for research has limited progress. We evaluated a large cohort of diffuse intrinsic pontine gliomas (DIPGs) to identify recurrent genomic abnormalities and gene expression signatures underlying DIPG. Patients and Methods: We used single nucleotide polymorphism arrays to evaluate genomic copy number imbalances in 43 DIPGs from 40 patients and in 8 low-grade exophytic brainstem gliomas. Gene expression arrays were used to evaluate expression signatures from 27 DIPGs, 6 low-grade exophytic brainstem gliomas and 66 low-grade gliomas arising outside the brainstem. Results: Frequencies of specific large-scale and focal imbalances varied significantly between DIPGs and pediatric glioblastomas outside the brainstem. Focal amplifications of genes within the receptor tyrosine kinase-Ras-PI3-kinase signaling pathway were found in 47% of DIPG, with PDGFRA and MET showing the highest frequency. 30% of DIPG contained focal amplifications of cell-cycle regulatory genes controlling RB phosphorylation, and 21% had concurrent amplification of genes from both pathways. Some tumors showed heterogeneity in amplification patterns. DIPGs showed distinct gene expression signatures relating to developmental processes compared to pediatric glioblastomas arising outside the brainstem, while expression signatures of low-grade exophytic brainstem gliomas were similar to low-grade gliomas outside the brainstem. Copy number analaysis: 43 DIPG samples, 8 Low Grade Gliomas using SNP6.0. Available matched normals are also profiled with SNP6.0. Expression analysis: 29 DIPG samples, 6 Low grade samples Please contact Suzanne Baker at Suzanne.Baker@stjude.org for CEL files and genotype calls.
Project description:Gliomas arising in the brainstem are rare tumours worldwide that are difficult to surgically resect, and the involved miRNAs and signaling pathways associated with brainstem gliomas (BSGs) are largely unclear. Tumours in the control nervous system owned a WHO classification, which are of great significance to guide the treatment and to evaluate prognosis. To determine grade-associated miRNAs in BSGs, this study performed microarray of 10 low-grade and 15 high grade BSGs.
Project description:Genome-wide DNA methylation profiling of 10 pediatric bithalamic diffuse gliomas. The Illumina Infiunium 450k Human DNA Methylation Beadchip (n=4) or the Infinium EPIC 850k Human DNA Methylation Beadchip (n=6) was used to obtain DNA methylation profiles across approximately 450,000 or 850,000 CpG sites of genomic DNA extracted from formalin-fixed, paraffin-embedded tumor tissue of 10 pediatric bithalamic diffuse gliomas.
Project description:Gliomas arising in the setting of neurofibromatosis type 1 (NF1) are heterogeneous, occurring from childhood through adulthood, can be histologically low-grade or high-grade, and follow an indolent or aggressive clinical course. Comprehensive profiling of genetic alterations beyond NF1 inactivation and epigenetic classification of these tumors remain limited. Through next-generation sequencing, copy number analysis, and DNA methylation profiling of gliomas from 47 NF1 patients, we identified 2 molecular subgroups of NF1-associated gliomas. The first harbored biallelic NF1 inactivation only, occurred primarily during childhood, followed a more indolent clinical course, and had a unique epigenetic signature for which we propose the terminology "pilocytic astrocytoma, arising in the setting of NF1". The second subgroup harbored additional oncogenic alterations including CDKN2A homozygous deletion and ATRX mutation, occurred primarily during adulthood, followed a more aggressive clinical course, and was epigenetically diverse, with most tumors aligning with either high-grade astrocytoma with piloid features or various subclasses of IDH-wildtype glioblastoma. Several patients were treated with small molecule MEK inhibitors that resulted in stable disease or tumor regression when used as a single agent, but only in the context of those tumors with NF1 inactivation lacking additional oncogenic alterations. Together, these findings highlight recurrently altered pathways in NF1-associated gliomas and help inform targeted therapeutic strategies for this patient population.