12167 results for "cancer rna-seq"

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• ERG ALTERATIONS DEFINE A NOVEL SUBTYPE OF ACUTE LYMPHOBLASTIC LEUKEMIA

  Structural chromosomal alterations are a hallmark of acute lymphoblastic leukemia (ALL) yet many patients lack an identifiable abnormality on conventional cytogenetic analysis. Here, using integrated analysis of genome-wide DNA copy number and gene expression data of 1764 childhood and adult ALL cases, including whole-genome, exome and mRNA-sequencing of 72 cases, we report a novel subtype of B-progenitor ALL (B-ALL) representing 4-13% of B-ALL cases characterized by a distinct gene expression profile, and focal deletions of ERG (ETS related gene) in 56% of cases. These cases are characterized by expression of a ERG transcript that utilizes a novel exon in intron 6 of ERG spliced to the canonical reading frame of ERG exons 7-10, encoding a 27 kDa C-terminal ERG protein that retains the ETS and transactivating domains but lacks the N-terminal pointed and regulatory domains. This protein is a competitive inhibitor of wild-type ERG and is leukemogenic in vivo. ERG-altered ALL cases have a favourable outcome despite the presence of alterations associated with poor prognosis in non-ERG ALL, such as deletions of IKZF1. These findings identify a new subtype of leukemia characterized by a novel mechanism of ETS transcription factor dysregulation in cancer.

  Study EGAS00001000514

• Comparison of structural variations from 10X Genomics linked-reads and conventional Illumina short-reads sequencing

  Structural variations (SVs) are large genomic rearrangements that can drive many diseases. Conventional short-reads whole genome sequencing (cWGS) allows their identification with base-pair resolution, but suffers from high false discovery rate. cWGS taps in short-range information from short-reads while linked-reads sequencing (10XWGS) utilizes long-range information. 10XWGS allows linkage of short-reads originating from the same large DNA molecule with a unique barcode captured in a gel bead in emulsion. This mitigates alignment-based artefacts from cWGS especially in repetitive regions. However, the false discovery rate of this technology is unclear. In this study, we performed a comprehensive analysis of different type and size of SVs predicted from these two technologies. The SVs common between both technologies were found to be highly specific by PCR and Sanger sequencing while validation rate dropped for uncommon events. Further, we propose a novel enrichment approach for filtering out false positive calls from both the technologies independently. To this end, we trained a machine learning model for respective technologies and used it to characterise SVs from MCF7 cell line and a primary breast cancer tumor with high precision. This approach would be valuable in understanding true mechanisms driven by SVs in various diseases.

  Study EGAS00001004093

• Inhibiton of the GABPB1L-containing GABP tetramer is sufficient to reverse replicative immortality in TERT promoter mutant glioblastoma cells.

  Over 50 types of cancer acquire TERT promoter mutations. These single point mutations reactivate telomerase, allowing for indefinite maintenance of telomere length and enabling cellular immortalization. The transcription factor binding site created by the point mutations specifically recruit the ETS factor GABP, a multimeric transcription factor composed of the GABPα and GABPβ subunits. GABP can form two functionally independent transcription factor species – a dimer or a tetramer – depending on which of the structurally distinct GABPβ isoforms is incorporated into the complex. In this study, we show that genetic disruption of GABPβ1L, a tetramer forming isoform of GABPβ that is dispensable in normal development, results in TERT silencing in a TERT promoter mutation dependent manner. Failure to activate TERT expression by GABPβ1L culminates in telomere dysfunction, DNA damage, and mitotic cell death exclusively in TERT promoter mutant cells. Furthermore, exogenous expression of TERT is sufficient to prevent telomere degradation and loss of cell viability in GABPβ1L-reduced lines bearing the mutant TERT promoter. Orthotopic injection of tetramer-deficient mutant TERT promoter GBM cells rendered lower tumor burden and prolonged the overall survival of the tumor-bearing mice. These results highlight the potentially widespread role of GABPB1L in enabling replicative immortality of TERT promoter cancers.

  Study EGAS00001002582

• Single-cell profiling reveals mechanisms of response to anti-PD-L1 versus anti-PD-L1 combined with anti-CTLA4 in head and neck squamous cell carcinoma

  Cancer patients often receive a combination of PD-(L)1 and CTLA4 inhibitors, but the mechanisms underlying their concerted actions remain unclear. We conducted a neoadjuvant study in head and neck squamous cell carcinoma (HNSCC) involving anti-PD-L1 monotherapy versus anti-PD-L1/anti-CTLA4 combination. Single-cell profiling of on- versus pre-treatment biopsies confirmed T-cell expansion as response biomarker. We identified a type 1 immune response accompanying T-cell expansion on-treatment across treatment arms, and herein characterized co-localized IgG plasma cell expansion as important contributor. In pre-treatment biopsies, similar features correlated with expansion upon anti-PD-L1, but not anti-PD-L1/anti-CTLA4. By profiling tumor-draining lymph nodes, we found the addition of anti-CTLA4 to trigger activation and subsequent trafficking of CD4+ T-cells via the blood, to become T-helper 1 cells in the tumor. anti-PD-L1/anti-CTLA4 indeed facilitated co-localized expansion of CD4+ and CD8+ T-cells in tumors versus mostly CD8+ T-cells with anti-PD-L1 alone. Hence, we identify complimentary mechanisms underlying anti-PD-L1/anti-CTLA4 therapy in HNSCC.

  Study EGAS50000000037

• Whole exome sequencing on primary retinoblastoma tissues and matching lymphocyte DNA.

  Retinoblastoma is a rare childhood cancer initiated by RB1 mutation or MYCN amplification, while additional alterations may be required for tumor development. However, the view on single nucleotide variants is very limited. To better understand oncogenesis, we determined the genomic landscape of retinoblastoma. We performed exome sequencing of 71 retinoblastomas and matched blood DNA. Next, we determined the presence of single nucleotide variants, copy number alterations and viruses. Aside from RB1, recurrent gene mutations were very rare. Only a limited fraction of tumors showed BCOR (7/71, 10%) or CREBBP alterations (3/71, 4%). No evidence was found for the presence of viruses. Instead, specific somatic copy number alterations were more common, particularly in patients diagnosed at later age. Recurrent alterations of chromosomal arms often involved less than one copy, also in highly pure tumor samples, suggesting within-tumor heterogeneity. Our results show that retinoblastoma is among the least mutated cancers and signify the extreme sensitivity of the childhood retina for RB1 loss. We hypothesize that retinoblastomas arising later in retinal development benefit more from subclonal secondary alterations and therefore, these alterations are more selected for in these tumors. Targeted therapy based on these subclonal events might be insufficient for complete tumor control.

  Study EGAS00001001690

• Host whole genome variations are associated with neurocognitive outcome in survivors of pediatric medulloblastoma

  Host whole genome analysis is a promising source of predictive information for long-term morbidity in cancer survivors. However, studies on genetic predictors of long-term outcome, particularly neurocognitive function following chemoradiation in pediatric oncology are limited. In the present study, we evaluated variations in host whole genome single nucleotide polymorphisms (SNPs) and their association with cognitive outcome. Whole-genome SNP analysis of host peripheral blood was conducted on 22 medulloblastoma long-term survivors, of whom 18 completed neuropsychological testing. First, unsupervised consensus clustering of the most variable SNPs within 409 genes involved in DNA repair was performed. Discrete variant groups were identified, although they were not associated with cognitive outcome, suggesting that variations in genes corresponding to a single functional group may be insufficient to predict long-term outcome alone. In support of this interpretation, unsupervised hierarchical clustering analysis using disease-associated gene variants by cognitive impairment status yielded two distinct variant clusters comprised of 36 variants, 34 of which were in noncoding regions. These findings illustrate for the first time that cognitively impaired survivors have a distinct variant profile compared to other medulloblastoma survivors. Future research in larger cohorts is needed to validate host genome predictors of cognitive impairment that may impact clinical management.

  Study EGAS00001002996

• IFN-γ and TNF-α drive a CXCL10+ CCL2+ Macrophage Phenotype Expanded in Severe COVID-19 Lungs and Inflammatory Diseases with Tissue Inflammation

  We explored how the human macrophages response to different inflammatory factors, focusing particularly on the effects of antiviral interferons (IFN-β and IFN-γ), pro-inflammatory cytokines such as TNF-α, and other mediators like IL-4. Co-cultured fibroblasts were a component in some conditions to generate factors produced by resident stroma. We used a single-cell antibody-based hashing strategy to multiplex samples from different stimulatory conditions in one sequencing run. This macrophage transcriptomic data reveals distinct macrophage activation states and polarizations shaped by different tissue-related inflammatory conditions at single-cell resolution. We further performed an unbiased integration between tissue-level macrophages and this stimulated human blood-derived macrophages, which pinpoint an IFN-γ and TNF-α synergistically driven inflammatory macrophage phenotype expanded in severe COVID-19 lungs and other inflamed disease tissues.

  Study phs002780

• A Multimodal Atlas of Human Brain Cell Types

  "A multimodal atlas of human brain cell types" includes sample data targeting two cell types that show species differences between mouse and human. First, it includes a detailed transcriptomic, morphological, and electrophysiological characterization of cell types in layer 1 of human middle temporal gyrus, focusing primarily on different inhibitory cell types. This project also includes gene expression data collected from nuclei in layer 5 of human fronto-insula, with a goal of identifying transcriptomic signatures of Von Economo neurons. Control samples collected as part of the same experiment are also included in the data set. This study was conducted as part of a collaboration between the Allen Institute for Brain Science, the University of Szeged, and the J. Craig Venter Institute. Collaborators request that publications resulting from these data cite their original publication: Transcriptomic and morphophysiological evidence for a specialized human cortical GABAergic cell type (PMID: 30150662).

  Study phs001791

• DNA and RNA sequencing of single human haploid germ cells

  Our goal was to look at allele-specific gene expression in single spermatids from two human donors. We first genotyped and phased each donor using a combination of linked-read sequencing (one sample per donor, 10X Chromium), and single haploid whole genome sequencing (53 spermatids for the first donor, and 19 for the second). We then sequenced mRNA from single spermatids (302 from the first donor, and 164 from the second), using the Smart-Seq2 protocol. We used these gene expression data, in combination with the haplotype data, to look for gene products that exhibit allele-specific bias reflecting the haploid genotype of the cell. We find a large class of human genes that show such allele-specific bias in spermatids, indicating that these gene products are not fully shared across the cytoplasmic bridges that connect spermatids. We term these genes “genoinformative markers” (GIMs).

  Study phs002279

• Whole genome sequencing data from tumor and normal samples

  Whole genome sequencing FASTQ files from tumor and normal samples from 202 patients. All experiments reported in this article were performed in the Clinical Laboratory Improvement Amendments (CLIA)-certified and College of American Pathologists (CAP)-accredited laboratories at Personalis Inc., as guided by the Association for Molecular Pathology (AMP) and CAP’s joint recommendations52. Preferred input material consisting of FFPE slides (enabling H&E and macrodissection which is part of the standard NeXT Personal process) was not available for the majority (94%) of tumor samples. Most tumor samples (72%) were processed from FFPE curls, with the remaining processed from pre-extracted DNA and fresh frozen material. Where FFPE material on slide was available, tumor sections were macrodissected to increase tumor content, with a minimum allowable cellularity threshold of 20% determined by pathological review. The tumor cellularity threshold of 20% was chosen based on prior work demonstrating that no significant correlation is observed between tumor purity and assay limit of detection (LOD) at this threshold31. Genomic DNA was isolated from tumor and normal samples and WGS libraries prepared as previously described31. Genomic DNA was isolated from matched tumor and normal samples using the Qiagen AllPrep DNA/RNA FFPE Tissue Kit or the QIAamp DNA Mini Kit (QIAGEN, Germantown, MD, USA) using internally optimized workflows. WGS sequencing libraries were prepared with 120-500 ng of acoustically sheared genomic DNA (Covaris LLC, Woburn, MA, USA) using the KAPA HyperPrep Kit (Roche Sequencing Solutions, Pleasanton, CA, USA) and customized methods. Libraries were cleaned-up using AMPure XP beads and then quantified using the KAPA Library Quantification Kit (Roche Sequencing Solutions, Pleasanton, CA, USA), before being sequenced to 30X depth of coverage using a NovaSeq 6000 instrument (Illumina, San Diego, CA, USA).

  Dataset EGAD50000001909