4913 results for "*oma"

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• Whole Genome Sequencing of Neuroblastoma

  Neuroblastoma is a childhood tumour of the peripheral sympathetic nervous system. The pathogenesis has for a long time been quite enigmatic, as only very few gene defects were identified in this often lethal tumour1. Frequently detected gene alterations are limited to MYCN amplification (20%) and ALK activations (7%)2-5. Here we present a whole genome sequence analysis of 87 neuroblastoma of all stages. Only few recurrent amino-acid changing mutations were found. In contrast, analysis of structural defects identified in 18% of high stage neuroblastoma a local shredding of chromosomes, known as chromothripsis6. These tumours are associated with a poor outcome. Structural alterations recurrently affected ODZ3, PTPRD and CSMD1, which are involved in neuronal growth cone stabilization7-9. In addition, ATRX, TIAM1 and a series of regulators of the Rac Rho pathway were mutated, further implicating defects in neuritogenesis in neuroblastoma. Most tumors with defects in these genes were aggressive high stage neuroblastoma, but did not carry MYCN amplifications. The genomic landscape of neuroblastoma therefore reveals two novel molecular defects, chromotripsis and neuritogenesis gene alterations, which frequently occur in high risk tumors.

  Study EGAS00001000222

• Driver mutations in histone H3.3 and chromatin remodelling genes in paediatric glioblastoma

  Glioblastoma multiforme (GBM) is a lethal brain tumour in adults and children. However, DNA copy number and gene expression signatures indicate differences between adult and paediatric cases. To explore the genetic events underlying this distinction, we sequenced the exomes of 48 paediatric GBM samples. Somatic mutations in the H3.3-ATRX-DAXX chromatin remodelling pathway were identified in 44% of tumours (21/48). Recurrent mutations in H3F3A, which encodes the replication-independent histone 3 variant H3.3, were observed in 31% of tumours, and led to amino acid substitutions at two critical positions within the histone tail (K27M, G34R/G34V) involved in key regulatory post-translational modifications. Mutations in ATRX (alpha-thalassaemia/mental retardation syndrome X-linked) and DAXX (death-domain associated protein), encoding two subunits of a chromatin remodelling complex required for H3.3 incorporation at pericentric heterochromatin and telomeres, were identified in 31% of samples overall, and in 100% of tumours harbouring a G34R or G34V H3.3 mutation. Somatic TP53 mutations were identified in 54% of all cases, and in 86% of samples with H3F3A and/or ATRX mutations. Screening of a large cohort of gliomas of various grades and histologies (n=784) showed H3F3A mutations to be specific to GBM and highly prevalent in children and young adults. Furthermore, the presence of H3F3A/ATRX-DAXX/TP53 mutations was strongly associated with alternative lengthening of telomeres and specific gene expression profiles. This is, to our knowledge, the first report to highlight recurrent mutations in a regulatory histone in humans, and our data suggest that defects of the chromatin architecture underlie paediatric and young adult GBM pathogenesis.

  Study EGAS00001000226

• A Comprehensive Catalogue of Somatic Mutations from a Human Cancer Genome

  We previously reported the whole-genome sequencing of the well-studied human malignant melanoma cell line, COLO-829, and a lymphoblastoid cell line from the same individual, providing the first comprehensive catalogue of somatic mutations from an individual cancer (Pleasance et al. (2010) Nature 463, 191). This initial study was carried out using the Illumina Genome Analyzer II, largely using paired-end reads of 75 bases from standard Illumina paired-end libraries. Here we report the results of sequencing the genomes of COLO-829 and its matched lymphoblastoid sample using HiSeq2000 with v3 cluster-generation and sequencing chemistries. This has significantly improved the evenness and completeness of genomic coverage, particularly in areas of extreme sequence composition that were underrepresented in the initial study.

  Study EGAS00001000245

• Inferring tumor genomes from peripheral blood i.e. CTCs and plasma-DNA using deep sequencing and targeted enrichment

  In this study we tested whether complex tumor genomes can be inferred from the peripheral blood (plasma DNA /CTCs) of 32 patients with stage IV colorectal carcinoma (CRC). To establish the percentage of mutated plasma DNA fragments we used 8 patient samples with different plasma DNA size distributions and KRAS mutations in their corresponding primary tumors and employed ultra-deep pyrosequencing with 3 different sequencing reaction sizes (i.e., 119 bp, 168 bp, and 323 bp). Furthermore, we used massive parallel sequencing of a panel of 68 CRC-associated genes to establish the mutation spectrum of cancer driver genes in the primary tumors, metastases, and CTCs of two colorectal cancer patients. To investigate, whether mutations found in only one CTC (“private CTC mutations”) are true mutations occurring with allele frequencies below the resolution limits of current detection methods, or whether they are amplification or sequencing artifacts, we performed ultra-deep sequencing of the primary tumors, metastases, plasma DNAs and normal tissues.

  Study EGAS00001000337

• Genetic landscape of pediatric Retinoblastoma

  Retinoblastoma is a pediatric cancer of the developing retina. All retinoblastomas are believed to initiate with biallelic inactivation of the RB1 gene. To identify subsequent genetic lesions in retinoblastoma, we performed whole genome sequencing of tumor and normal DNA of 4 children with retinoblastoma and one matched orthotopic xenograft. Both alleles of RB1 were inactivated in the tumor samples. 3 of the patients had sporadic retinoblastoma and one patient had inherited retinoblastoma. Overall, there were few single nucleotide changes in coding regions of the genome and some of the tumors had few chromosomal lesions. There were very few new genetic lesions in the xenograft compared to the primary tumor. These data suggest that the genome in retinoblastoma is more stable than previously believed and there are relatively few recurrent genetic lesions in known cancer pathways other than the RB1 pathway.

  Study EGAS00001000346

• Whole-genome-Sequencing of adult medulloblastoma

  Brain tumors constitute the childhood tumors with the highest mortality rates and survival is often associated with severe long-term sequelae due to intensive multimodal treatment regimens. Thus, the PedBrainTumor network aims at the identification of robust biomarkers for clinical management and novel molecular targets for therapeutic interventions. Using massively parallel whole-genome sequencing, and transcriptome and methylome sequencing for subsets of cases, we aim to decipher the molecular causes of medulloblastoma as well as low-grade astrocytoma, and to identify markers to stratify patients for specialized treatment. As the PedBrain network is affiliated with clinical trials in medulloblastoma and pilocytic astrocytoma, validation cohorts for the translation of key findings into clinical settings are readily available.

  Study EGAS00001000393

• Whole genome sequencing of chondrosarcoma

  Massive parallel sequencing of 10 chondrosarcoma genomes was conducted to identify somatic mutations, structural alterations including fusion genes and mutation signatures that may help to comprehensively characterize the molecular features.

  Study EGAS00001000505

• an integrated molecular study of clear cell renal cell carcinoma (ccRCC) including whole-genome/exome and RNA sequencing as well as array-based gene expression/copy-number/methylation analyses

  an integrated molecular study of clear cell renal cell carcinoma (ccRCC) including whole-genome/exome and RNA sequencing as well as array-based gene expression/copy-number/methylation analyses

  Study EGAS00001000509

• Multimodal antigenic escape to GPRC5D-targeted T-cell engagers in multiple myeloma

  We analyzed the genome of plasma cells collected from bone marrow samples or plasmocytoma from patients prior to (when available) and progression on anti-GPRC5D T cell engagers.

  Study EGAS50000001148

• ABO: a 3D stroma-supported culture platform enabling full human B lymphopoiesis for disease modeling and gene therapy development

  Defective B-cell development underlies a large proportion of inborn errors of immunity, but progress in understanding disease mechanisms and of developing therapies has been limited by inadequate human in vitro models. Here, we establish a 3D aggregate culture platform composed of hematopoietic stem and progenitor cells (HSPCs) and mouse bone marrow stromal cells as an assay for efficient B-cell output (the ABO platform). ABOs supported progression through pro-B, pre-B, immature, and transitional B-cell stages, with a transcriptional profile and B-cell receptor (BCR) repertoire diversity closely resembling human bone marrow B-cell ontogeny. ABO-derived B cells exhibited functional signaling and differentiated into class-switched memory and antibody-secreting B cells following CD40-mediated stimulation. The ABO platform reproduced the arrest in B-cell development observed in RAG1-SCID patient–derived HSPCs, which was corrected by lentiviral RAG1 gene therapy. Thus, ABOs provide a clinically relevant platform for modeling B-cell immunodeficiencies and evaluating therapeutic strategies.

  Study EGAS50000001693