22951 results for "ega"

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• Divergence between high metastatic tumor burden and low circulating tumor DNA concentration in metastasized breast cancer

  Circulating tumor DNA (ctDNA) was reported to represent a highly sensitive biomarker of metastatic cancer disease directly reflecting tumor burden and dynamics. Here we investigated the role of ctDNA in patients with metastatic breast cancer. In an index patient with more than 100,000 circulating tumor cells (CTCs) in serial blood analyses, whole genome, exome, or targeted deep sequencing of the primary tumor, metastases, and 551 CTCs were consistent with a genetically homogeneous cancer. However, the allele fractions (AFs) of ctDNA were only 2-3% in each analysis, which did neither reflect the tumor burden nor the dynamics of this progressive disease by far. Indeed, plasma analyses of 71 further patients demonstrated highly variable AFs of mutant fragments, which frequently did not correspond to the tumor burden. These results provide insights into mechanisms involved in CTC and ctDNA release into the circulation and have important implications for diagnostic tests based on liquid biopsies.

  Study EGAS00001000625

• Transcriptional and functional profiling defines human small intestinal macrophage subsets

  Macrophages (Mf) are instrumental in maintaining immune homeostasis in the intestine, yet studies on origin and heterogeneity of human intestinal Mf are scarce. Here, we identified four distinct Mf subpopulations in human small intestine (SI). Assessment of their turnover in duodenal transplants revealed that all Mf subsets were completely replaced over time; Mf1 and Mf2, phenotypically similar to peripheral blood monocytes (PBMo), were largely replaced within 3 weeks, whereas two subsets with features of mature Mf, Mf3 and Mf4, exhibited significantly slower replacement. Mf3 and Mf4 localized differently in SI; Mf3 formed a dense network in mucosal lamina propria, whereas Mf4 was enriched in submucosa. Transcriptomic analysis showed that all Mf subpopulations subsets were markedly distinct from PBMo and dendritic cells (DC). Compared to PBMo, Mf subpopulations showed reduced responsiveness to proinflammatory stimuli, but were proficient at endocytosis of particulate and soluble material. These data provide a comprehensive analysis of human SI Mf population and suggest a precursor-progeny relationship with PBMo.

  Study EGAS00001002093

• Resequencing_candidate_genes_for_male_spermatogenic_impairment

  This study aims to identify novel candidate variants from human Y-chromosomal genes DAZ, BPY2 and CDY1 by resequencing the coding regions of these genes from male patients with spermatogenic impairment. The coding regions of the genes have been amplified by standard PCR, amplicon lengths range from 244 to 486 bp. A total of 61 amplicons were amplified for each of the 96 patients, totalling to approx. 25 kb per sample. Amplicons were quantified by gel electrophoresis and pooled in approx. equimolar concentrations per patient. For each of the 96 submitted samples, approx. 1 microgram of amplified DNA pool is provided in a total volume of 120 microlitres. The samples need to be indexed and libraries prepared for a PE250bp Illumina MiSeq run. This data is part of a pre-publication release. For information on the proper use of pre-publication data shared by the Wellcome Trust Sanger Institute (including details of any publication moratoria), please see http://www.sanger.ac.uk/datasharing/

  Study EGAS00001002157

• Data from the paper Context-specific Effects of TGFβ/SMAD3 in Cancer Are Modulated by the Epigenome. Tufegdzic et al, Cell Reports 2015

  The transforming growth factor beta (TGFβ) signalling pathway exerts opposing effects on cancer cells, acting either as a tumor-promoter or as a tumor-suppressor. Here we show these opposing effects are a result of the synergy between SMAD3, a downstream effector of TGFβ signalling, and the distinct epigenomes of breast tumor initiating cells (BTICs). These effects of TGFβ are associated with distinct gene expression programs, but genomic SMAD3 binding patterns are highly similar in the BTIC-promoting and BTIC- suppressing contexts. Our data show cell type-specific epigenetic configurations provide a modulatory layer by determining accessibility of genes to regulation by TGFβ/SMAD3. LBH, one such context-specific target gene, is regulated according to its DNA methylation status, and is crucial for TGFβ-dependent promotion of BTICs. Overall, these results reveal that the epigenome plays a central and previously overlooked role in shaping the context-specific effects of TGFβ in cancer.

  Study EGAS00001001570

• The spatial organization of intratumor heterogeneity andevolutionary trajectories of metastases in hepatocellular carcinoma

  Hepatocellular carcinoma (HCC) has one of the poorest survival amongst cancers. Using multi-regional sampling of nine resected HCC with different etiologies, we find that phylogenetic relationships of these sectors show diverse levels of genetic sharing spanning early to late diversification. Unlike the variegated pattern found in colorectal cancers, a large proportion of HCC display a clear Isolation-By-Distance pattern where spatially closer sectors are genetically more similar. Two resected intra-hepatic metastases showed genetic divergence occurring before and after primary tumor diversification respectively. Interestingly, metastatic tumors had much higher variability than their primary tumors, suggesting that intra-hepatic metastasis is accompanied by rapid diversification at the distant location. The presence of co-existing mutations offers the possibility of drug repositioning for HCC treatment. Taken together, these insights into intra-tumor heterogeneity allow for a comprehensive understanding of the evolutionary trajectories of HCC and suggest novel avenues for personalized therapy.

  Study EGAS00001001603

• Single cell RNA sequencing and Whole Genome Sequencing on different cells from the same sample for a triple negative patient derived xenograft and ovarian cancer cell lines.

  Measuring gene expression of genomically defined tumour clones at single cell resolution would associate functional consequences to somatic alterations, as a prelude to elucidating pathways driving cell population growth, resistance and relapse. In the absence of scalable methods to simultaneously assay DNA and RNA from the same single cell, independent sampling of cell populations for parallel measurement of single cell DNA and single cell RNA must be computationally mapped for genome-transcriptome association. Here we present clonealign, a robust statistical framework to assign gene expression states to cancer clones using single-cell RNA-seq and DNA-seq independently sampled from an heterogeneous cancer cell population. We apply clonealign to triple-negative breast cancer patient derived xenografts and high-grade serous ovarian cancer cell lines and discover clone-specific dysregulated biological pathways not visible using either DNA-Seq or RNA-Seq alone.

  Study EGAS00001003387

• Next_gen_seq_of_eye_cancers

  Retinoblastoma (RB), the commonest eye cancer in children was the first cancer for which a genetic cause was identified: the Rb1 gene is a tumour suppressor gene that is mutated in RB. The Rb1 gene defect alone does not predict the clinical outcome. We propose to study other possible mechanisms: 1. Stepwise further mutations occur in RB, increasing its carcinogenesis. We will sequence the whole genome in RB tissue, and relate the different genes expressed to the treatments used. 2. Extracellular matric proteins contribute to a tumour permissive environment for RB to continue to grow. This includes Samll Leucine Rich Proteoglycans (SLRP), a family of 15 secreted extracellular matrix proteins involved in eye development. 3. Cancer stem cells (CSC), a subpopulation of treatment resistant cells, drive RB tumours, and whether these stem cells can be manipulated for new therapies. The aim of this study is to assist finding targeted diagnostic techniques and treatments for RB.

  Study EGAS00001002309

• Reference epigenomes generated as part of the International Human Epigenomics Consortium (IHEC)

  The Centre for Epigenome Mapping Technologies (CEMT) is an epigenome sequencing platform funded by the Canadian Institutes of Health Research (CIHR) and Genome BC as part of the Canadian Epigenetics, Environment and Health Research Consortium (CEEHRC). CEMT aims to produce 100 human reference epigenomes, each comprising the following datasets: whole genome; whole genome bisulfite and oxidative bisulfite; transcriptome; microRNA; and chromatin immunoprecipitation (ChIP)-seq for the core chromatin marks (H3K4me1, H3K4me3, H3K9me3, H3K27me3, H3K36me3, and H3K27ac).CEEHRC is a full member of the International Human Epigenomics Consortium (IHEC), which aims to coordinate the production of 1,000 reference maps of human epigenomes for key cellular states relevant to health and diseases. As such, all datasets submitted by the CEMT platform conform to IHEC assay standards and metadata guidelines.

  Study EGAS00001000552

• Genomic catastrophes frequently arise in esophageal adenocarcinoma and drive tumorigenesis.

  Oesophageal adenocarcinoma (EAC) incidence is rapidly increasing in Western countries. A better understanding of EAC underpins efforts to improve early detection and treatment outcomes. While large EAC exome sequencing efforts to date have found recurrent loss-of-function mutations, oncogenic driving events have been underrepresented. Here we use a combination of whole-genome sequencing (WGS) and single-nucleotide polymorphism-array profiling to show that genomic catastrophes are frequent in EAC, with almost a third (32%, n=40/123) undergoing chromothriptic events. WGS of 22 EAC cases show that catastrophes may lead to oncogene amplification through chromothripsis-derived double-minute chromosome formation (MYC and MDM2) or breakage-fusion-bridge (KRAS, MDM2 and RFC3). Telomere shortening is more prominent in EACs bearing localized complex rearrangements. Mutational signature analysis also confirms that extreme genomic instability in EAC can be driven by somatic BRCA2 mutations. These findings suggest that genomic catastrophes have a significant role in the malignant transformation of EAC.

  Study EGAS00001000750

• Tracking the genomic evolution of esophageal adenocarcinoma through neoadjuvant chemotherapy

  Esophageal adenocarcinomas (EACs) are associated with dismal prognosis. Deciphering the evolutionary histories of this disease may shed light on therapeutically tractable targets and reveal changing mutational processes during the disease course and following neoadjuvant chemotherapy (NAC). We exome sequenced 40 tumor regions from 8 patients with operable EACs both before and after platinum-containing NAC. This revealed the evolutionary genomic landscape of EACs with the presence of heterogeneous driver mutations, parallel evolution, early genome doubling events and an association between high intratumor heterogeneity and poor response to NAC. Multi-region sequencing demonstrated a significant reduction in T>G mutations within a CTT context when comparing early and late mutational processes and the presence of a platinum signature with enrichment of C>A mutations within a CpC context following NAC. EACs are characterized by the presence of amplifications containing targetable oncogenes present before and after chemotherapy that may provide a rationale for future therapeutic approaches.

  Study EGAS00001001254