14977 results for "cancer studies using rna-seq"

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• GeneScreen, a Population Based, Targeted Genomic Screening Study

  The GeneScreen research study was based at the University of North Carolina (UNC) at Chapel Hill. It brought together researchers from different disciplines, including genetics, clinical medicine, bioethics, sociology, anthropology, psychology, and public health, to study the best ways to offer targeted genetic screening to the general adult population. DNA samples were collected from people who joined GeneScreen to look at a targeted panel of 17 genes. It tested for genetic differences (called mutations) that can cause one of 11 rare, but preventable or treatable conditions, including certain types of cancer and heart disease. Each condition has specific medical advice people can follow with their doctors to prevent or treat a serious health problem. The GeneScreen study was approved by the UNC Institutional Review Board and by the Kaiser Permanente Center for Health Research Institutional Review Board. GeneScreen is funded by the National Human Genome Research Institute of the National Institutes of Health.

  Study phs001817

• Metastatic Colorectal Adenocarcinoma Tumor Purity Assessment from Whole Exome Sequencing Data

  As molecular medicine wields greater and greater influence on cancer patient care, including therapeutic selection, it becomes increasingly important to understand the power and deficiencies of computational tools used in decision making processes. Here we use a set of unselected metastatic colorectal tumor samples in a head-to-head comparison between the calculation of stromal content by a board certified pathologist, versus that derived from whole exome sequencing and purity assessment by a variety of common computational methods. We find that in about 1/2 of the samples the computational methods each do a poor job of assessing the percent stromal contamination, and as a result, tumor variant allele frequencies (VAFs) are low or undetected, whereas analysis of organoids derived from the same tumors yielded much higher VAFs in keeping with their lower stromal content. The whole exome sequence of our samples is available via dbGaP, accession phs003059.v1.p1.

  Study phs003059

• California Teachers Study (CTS): Whole Genome Sequences From Under-Represented Populations

  The California Teachers Study (CTS) is a prospective observational cohort of N=133,477 adult women who have been followed since 1995. Participants completed up to six surveys and have been linked with cancer, hospitalization, and mortality data. In 2013-2016, over 14,000 CTS participants donated blood samples for future research. For this project, DNA was extracted in 2023 from 1694 buffy coats and 56 blood clots from N=1750 CTS participants whose self-reported race/ethnicity was Asian (398), Asian or Pacific Islander (18), Black or African American (189), Native American (128), Native Hawaiian or Other Pacific Islander (66), White Hispanic (719), or more than one race (232). Whole genome sequencing (WGS) was performed at CIDR in 2023-2024. WGS data and accompanying phenotype data are available through dbGaP. In addition, all CTS data are available to the research community via the CTS Researcher Platform (www.calteachersstudy.org), a secure cloud-based environment that includes data, software, documentation, and collaboration workspaces.

  Study phs002918

• Identifying genetic variants that alter TCR usage in the peripheral repertoire

  The relationship between genetic variation and CD8+ T-cell receptor (TCR) repertoire usage in patients receiving Immune Checkpoint Blockade (ICB) therapy for cancer is unexplored. We have conducted a genome-wide and human leukocyte antigen (HLA)-focused analysis of CD8+ T-cell TCR repertoire to identify genetic determinants of variable gene (V-gene) and CDR3 K-mer usage from samples taken prior to and after ICB (n=250). We identify 11 cis and 10 trans V-gene associations, primarily to the MHC, that meet genome-wide significance. TCR clones containing HLA associated V-genes were less stable across treatment, whilst at the single-cell level, genetically associated clones demonstrate subset enrichment and increased tumor reactivity expression profiles. Notably, patients with HLA-matched TCR clones demonstrate improved overall survival. Our work indicates a complex relationship between genotype and TCR repertoire in the context of ICB treatment, with novel implications for understanding factors relating to therapeutic response and patient outcomes.

  Study EGAS00001008189

• Data Use Ontology (DUO) at EGA

  For those of you that follow the updates of GA4GH you will have seen the unanimous approval of the steering committee for DUO to be included in its suite of technical standards for the sharing of genomic and health related data. DUO has three main features: Each term has been generated by the community and includes a human readable definition that can be expanded where necessary. It is a machine-readable file that encodes how that data can be used and how a researcher intends to use the data. Can be implemented alongside an advanced search algorithm which would allow authenticated users to query and gain access to datasets pertaining to their research. e.g., an industry researcher working on cancer could potentially be matched to any dataset that is allowed for commercial use and for cancer research and offered the opportunity to fetch them automatically. So, what does this mean for EGA? EGA as a driver project has adopted this standard and will be utilizing it for two main purposes in the first instance. i) It will allow EGA users to instantly identify what terms they will need to agree to as part of any Data Access Agreements. This will save valuable time for both applicants and Data Access Committees alike - as you will be able to see if you are likely to be able to access the data based on your research intentions and working background. ii) In the future it will allow users to be able to search for data based on Data Use Ontology terms e.g., you could search for all data that can be used for General Research Use (GRU). As EGA moves forwards submitters will be asked to align their data access policies with DUO so that their dataset(s) can be tagged appropriately on our web pages. If you would like to add DUO to any of your existing datasets, or to any future datasets, do please just let us know.

  Blog data-use-ontology

• Spatial genomic heterogeneity in multiple myeloma revealed by multi- region sequencing

  The bone-marrow (BM) containing skeletal system is the reservoir of Multiple Myeloma (MM), the malignant counterpart of antibody-secreting plasma cells. To gain insight into its spatial clonal architecture, we performed multi-region whole-exome sequencing of radiology-guided fine-needle aspirates from 51 MM patients. We found spatial genomic heterogeneity in a substantial proportion of cases including bi-allelic inactivation of tumor suppressors and mutations affecting cancer genes. The amount of heterogeneous mutations associated with the size of focal tumor lesions in whole body imaging consistent with focal outgrowth of highly advanced clones. In conclusion, our results support the regional initiation of transformation processes leading to high-risk disease as well as the pre-existence of key driver events in restricted areas. As such, our study does not only provide new insights in the underlying biology of MM progression but also has considerable implications for standard diagnostic approaches in the clinic.

  Study EGAS00001002111

• CD74-NRG1 fusions in lung adenocarcinoma

  We discovered a novel somatic gene fusion, CD74-NRG1, by transcriptome sequencing of 25 lung adenocarcinomas of never smokers. By screening 102 lung adenocarcinomas negative for known oncogenic alterations we found four additional fusion-positive tumors, all of which were of the invasive mucinous subtype. Mechanistically, CD74-NRG1 leads to extracellular expression of the EGF-like domain of NRG1 III-beta3, thereby providing the ligand for ERBB2-ERBB3 receptor complexes. Accordingly, ERBB2 and ERBB3 expression was high in the index case and expression of phospho-ERBB3 was specifically found in tumors bearing the fusion (p<0.0001). Ectopic expression of CD74-NRG1 in lung cancer cell lines expressing ERBB2 and ERBB3 activated ERBB3 and the PI3K-AKT pathway, and led to increased colony formation in soft agar. Thus, CD74-NRG1 gene fusions are activating genomic alterations in invasive mucinous adenocarcinomas and may offer a therapeutic opportunity for a lung tumor subtype with, so far, no effective treatment.

  Study EGAS00001000653

• miR-200-regulated CXCL12β promotes fibroblast heterogeneity and immunosuppression in ovarian cancers

  High-grade serous epithelial ovarian cancer (HGSOC) has been recently subdivided into molecular subgroups, including the mesenchymal HGSOC associated with partial tumor-debulking surgery and poor patient survival. Consistent with stromal-related genes signatures defining mesenchymal HGSOC, we show here that stroma plays a key function in this HGSOC molecular subtype. We first highlight stromal heterogeneity in HGSOC by identifying 4 subsets of Carcinoma-Associated Fibroblast (CAF-S1-4). Mesenchymal HGSOC significantly accumulate the activated CAF-S1 subset, which exhibits immunosuppressive functions by promoting attraction, survival and activation of regulatory T-lymphocytes. The CXCL12β chemokine reliably characterizes mesenchymal HGSOC and specifically accumulates in the CAF-S1 subset through a regulation mediated by the miR-141/200a. CXCL12β promotes attraction of T-lymphocytes and is thus a key actor in CAF-S1-mediated immunosuppressive functions. In conclusion, we highlight here for the first time stromal heterogeneity and immunosuppression in mesenchymal HGSOC that could participate in the poor patient prognosis.

  Study EGAS00001002184

• Coverage bias and sensitivity of variant calling for four whole-genome sequencing technologies

  Massively parallel sequencing has revolutionized research in cancer genetics and genomics and enhanced our understanding of natural human genetic variation. Recently, Lam et al. have performed a detailed comparison of two next-generation sequencing technologies with respect to their sensitivity to call single nucleotide variants (SNV) and indels. Here, we sequenced two tumor/normal pairs obtained from two paedriatic medulloblastoma patients with Life Technologies’ SOLiD 4 and 5500xl SOLiD, Illumina’s HiSeq2000, and Complete Genomics’ technology. We then compared their ability to call SNVs with high confidence. As gold standard for SNV calling, we used genotypes determined by an Affymetrix SNP array. Additionally, we performed a detailed analysis of how evenly each technology covers the genome and how the reads are distributed across functional genomic regions. Finally, we studied how a combination of data from different technologies might help to overcome the limitations in SNV calling by any of the four technologies alone.

  Study EGAS00001000274

• Recurrent adeno-associated virus 2-related insertional mutagenesis in human hepatocellular carcinomas

  Hepatocellular carcinomas (HCC) are liver tumors related to various etiologies including alcohol intake, hepatitis B (HBV) or C (HCV) virus infection. Additional risk factors remain to be identified, particularly in patients who develop HCC without cirrhosis. We identified clonal integration of adeno-associated virus type 2 (AAV2) in 11 out of 193 HCC. These AAV2 integrations occurred within known cancer driver genes, namely, CCNA2 (Cyclin A2, 4 cases), TERT (Telomerase Reverse-Transcriptase, 1 case), CCNE1 (Cyclin E1, 3 cases), TNFSF10 (Tumor Necrosis Factor member 10, 2 cases) or KMT2B (Lysine (K)-Specific Methyltransferase 2B, 1 case) leading to over-expression of the target genes. Tumors with viral integration mainly developed in non-cirrhotic liver (9 out of 11 cases) and without known risk factors (6 out of 11) suggesting a pathogenic role of AAV2 in these patients. In conclusion, AAV2 is a DNA virus associated with oncogenic insertional mutagenesis in human HCC.

  Study EGAS00001001284

• Adult granulosa cell tumor WGS data cohort with corresponding reference germline WGS data

  Adult granulosa cell tumors (AGCTs) harbor a somatic FOXL2 c.402C>G mutation in ~95% of cases and are mainly surgically removed due to limited systemic treatment effect. In this study, potentially targetable genomic alterations in AGCTs were investigated by whole genome sequencing on 46 tumor samples and matched normal DNA. Copy number variant (CNV) analysis confirmed gain  of chromosome 12 and 14, and loss of 22. Pathogenic TP53 mutations were identified in three patients with highest tumor mutational burden and mitotic activity, defining a high-grade AGCT subgroup. Within-patient tumor comparisons showed 29-80% unique somatic mutations per sample, suggesting tumor heterogeneity. FOXL2-wildtype AGCTs had DICER1, TERT(C228T) and TP53 mutations and similar CNV profiles as FOXL2-mutant tumors. Our study confirms that absence of the FOXL2 c.402C>G mutation does not exclude AGCT diagnosis. The lack of overlapping variants in targetable cancer genes, indicates the need for personalized treatment for AGCT patients 

  Study EGAS00001004249

• Unraveling mutagenic processes influencing the tumor mutational patterns of individuals with Constitutional Mismatch Repair Deficiency

  Constitutional mismatch repair deficiency (CMMRD), caused by bi-allelic germline variants in one of the mismatch repair (MMR) genes, is a childhood cancer predisposition syndrome that often results in the development of multiple tumors early in life. A better understanding of mutational processes driving subsequent CMMRD tumors could advance optimal treatment. Therefore, we performed a genomic characterization of 41 tumors from 17 individuals with CMMRD. Mutational patterns in these tumors were found to be influenced by multiple factors, including the affected MMR genes, tumor types and somatic polymerase proofreading mutations. Temozolomide treatment left prominent mutational signatures in two second primary hematologic malignancies. Furthermore, a novel indel signature was found in 54% of the tumors, characterized by one base pair cytosine insertions in cytosine homopolymers. In conclusion, the analysis of sequential tumors in individuals with CMMRD reveals diverse mutational patterns influenced by the underlying mutated MMR gene, tumor type and treatment history.

  Study EGAS00001007660

• Utility of ctDNA to support patient selection for early phase clinical trials: The TARGET Study

  Next generation sequencing (NGS) of circulating tumour DNA (ctDNA) supports blood-based genomic profiling but is not routinely implemented in the clinic. TARGET is a molecular profiling programme with the primary aim to match patients to early phase clinical trials based on analysis of both somatic mutations and copy number alterations (CNA) across a 641 cancer-associated gene panel in a single ctDNA assay. For the first 100 TARGET patients, ctDNA data showed good concordance with matched tumour and results were turned round within a clinically acceptable timeframe for Molecular Tumour Board (MTB) review. When applying a 2.5% Variant Allele Frequency (VAF) threshold actionable mutations were identified in 41/100 patients, with 11 of these patients going onto a matched therapy. These data support the application of ctDNA in an early phase trial setting where broad genomic profiling of contemporaneous tumour material enhances patient stratification to novel therapies and provides a practical template for bringing blood-based analyses to the clinic.

  Study EGAS00001003407

• Dynamics of neoantigen landscape during immunotherapy

  Immune checkpoint inhibitors have shown significant therapeutic responses against tumors containing increased mutation-associated neoantigen load. We have examined the evolving landscape of tumor neoantigens during the emergence of acquired resistance in non-small cell lung cancer patients after initial response to immune checkpoint blockade with anti-PD1 or anti-PD-1/anti-CTLA4 antibodies. Analyses of matched pretreatment and resistant tumors identified genomic changes resulting in loss of 7 to 18 putative mutation-associated neoantigens in resistant clones. Peptides generated from the eliminated neoantigens elicited clonal T cell expansion in autologous T cell cultures, suggesting that they generated functional immune responses. Neoantigen loss occurred through elimination of tumor subclones or through deletion of chromosomal regions containing truncal alterations and were associated with changes in T cell receptor clonality. These analyses provide insights into the dynamics of mutational landscapes during immune checkpoint blockade and have implications for development of immune therapies that target tumor neoantigens.

  Study EGAS00001002704