3537 results for "*geneti*"

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• Genetic makeup of agnospheres

  Agnospheres are cultures of cancer stem cells isolated from tissue biopsies from patients with Cancer of Unknown Primary (CUPs). The latter is a lethal malignancy (median survival <1 year), representing approximately the 3% of all cancers, and characterized by metastatic dissemination in the absence of a primary tumor recognizable by a standardized protocol including thorough body imaging and histopathological analysis. Agnospheres are long-term propagated in culture and, after subcutaneous injection into immunocompromised mice, they display high tumorigenicity and quickly reproduce the clinical presentation of the original tumor, featuring a multi-organ metastatic pattern and poorly differentiated histology. The goal of the project is to analyse the mutational profile of agnospheres in detail, as to verify its correspondance with that of the original tumors. Genetic information will be exploited to investigate the genetic drivers of the CUP phenotype, in particular the hypermetastatic ability and the differentiative block.

  Study EGAS00001004868

• Genomic study of an AT-AML

  Ataxia Telangiectasia (A-T) is caused by biallelic mutations in ATM and confers predisposition to cancer, with acute myeloid leukaemia (AML) being rarely observed. We investigated an AML arising in an A-T patient for secondary genetic events by performing whole exome sequencing of serial samples over the disease course. AML samples were compared to a reference "germline" sample from a much earlier time point. Goldgraben et al 2020, Pediatric Blood & Cancer

  Study EGAS00001004392

• Whole Exome Sequencing of 60 tumor/normal matched liver Cancers (HCC)

  The French ICGC project on liver tumors is coordinated by Pr Jessica Zucman-Rossi and funded by Inca (French Institute for Cancer). The aim of the present project is to identify the catalog of somatic and germline mutations in liver tumors using whole genome (WGS) and whole exome sequencing (WGS), integrated with DNA methylation and RNA sequencing (RNA-seq) data. The present series corresponds to 60 whole exome tumor/normal pairs with matched RNA-seq. Hepatocellular carcinoma (HCC) accounts for more than 90% of liver cancers, and is a major health problem. It is the 3rd cause of cancer-related mortality. Advances in genomic analyses have formed a comprehensive understanding of different underlying pathobiological layers resulting in hepatocarcinogenesis. Thus, the development of next-generation sequencing technologies has made it possible to generate more comprehensive catalogues of somatic alteration events (single nucleotide substitutions, structural variations, and epigenetic changes) in liver cancer genome than ever before.

  Study EGAS00001003063

• Chemotherapy induces canalization of cell state in childhood B-cell precursor acute lymphoblastic leukemia

  Comparison of intratumor genetic heterogeneity in cancer at diagnosis and relapse suggests that chemotherapy induces bottleneck selection of subclonal genotypes. However, evolutionary events subsequent to chemotherapy could also explain changes in clonal dominance seen at relapse. We therefore investigated the mechanisms of selection in childhood B-cell precursor acute lymphoblastic leukemia (BCP-ALL) during induction chemotherapy where maximal cytoreduction occurs. To distinguish stochastic versus deterministic events, individual leukemias were transplanted into multiple xenografts and chemotherapy administered. Analyses of the immediate post-treatment leukemic residuum at single-cell resolution revealed that chemotherapy has little impact on genetic heterogeneity. Rather, it acts on extensive, previously unappreciated, transcriptional and epigenetic heterogeneity in BCP-ALL, dramatically reducing the spectrum of cell states represented, leaving a genetically polyclonal but phenotypically uniform population, with hallmark signatures relating to developmental stage, cell cycle and metabolism. Hence, canalization of the cell state accounts for a significant component of bottleneck selection during induction chemotherapy.

  Study EGAS00001004407

• Genome-wide associations of human gut microbiota variation and implications for causal inference analyses

  Here we use appropriate taxon-specific models along with support from independent cohorts to show association between human host genotype and gut microbiome variation. Using fecal derived 16S rRNA gene sequences and host genotype data from the Flemish Gut Flora Project (FGFP) we identify genetic associations involving multiple microbial traits. Mendelian randomization analysis was able to estimate associations between microbial traits and disease, however in the absence of clear microbiome driven effects, caution is needed in interpretation. This work marks a growing catalog of genetic associations which will provide insight into the contribution of host genotype to gut microbiome. Despite this, the uncertain origin of association signals will likely complicate future work looking to dissect function or use associations for causal inference analysis.

  Study EGAS00001004420

• Targeted sequencing CYLD cutaneous syndrome

  Patients with CYLD cutaneous syndrome (CCS; syn. Brooke-Spiegler syndrome) carry germline mutations in the tumor suppressor CYLD and develop multiple skin tumors with diverse histophenotypes. We comprehensively profiled the genomic landscape of 42 benign and malignant tumors across 13 individuals from four multigenerational families. Novel recurrent mutations were found in epigenetic modifiers DNMT3A and BCOR in 29% of benign tumors. Multi-level and microdissected sampling strikingly reveal that many clones with different DNMT3A mutations exist in these benign tumors, suggesting that intra-tumor heterogeneity is common. Integrated genomic, methylation and transcriptomic profiling in selected tumours suggest that isoform specific DNMT3A2 mutations are associated with dysregulated Wnt/ß-catenin pathway signaling. Phylogenetic and mutational signature analyses confirm cylindroma pulmonary metastases from primary skin tumours. These findings add novel dimensions to existing paradigms of cutaneous tumorigenesis and metastasis.

  Study EGAS00001003840

• RNA sequencing CYLD cutaneous syndrome

  Patients with CYLD cutaneous syndrome (CCS; syn. Brooke-Spiegler syndrome) carry germline mutations in the tumor suppressor CYLD and develop multiple skin tumors with diverse histophenotypes. We comprehensively profiled the genomic landscape of 42 benign and malignant tumors across 13 individuals from four multigenerational families. Novel recurrent mutations were found in epigenetic modifiers DNMT3A and BCOR in 29% of benign tumors. Multi-level and microdissected sampling strikingly reveal that many clones with different DNMT3A mutations exist in these benign tumors, suggesting that intra-tumor heterogeneity is common. Integrated genomic, methylation and transcriptomic profiling in selected tumours suggest that isoform specific DNMT3A2 mutations are associated with dysregulated Wnt/ß-catenin pathway signaling. Phylogenetic and mutational signature analyses confirm cylindroma pulmonary metastases from primary skin tumours. These findings add novel dimensions to existing paradigms of cutaneous tumorigenesis and metastasis.

  Study EGAS00001003841

• Glioblastoma initiating cells are sensitive to histone demethylase inhibition due to epigenetic deregulation

  Tumor-initiating cells are a subpopulation of cells that have self-renewal capacity to regenerate a tumor. Here, we identify stem cell-like chromatin features in human glioblastoma initiating cells (GICs) and link them to a loss of the repressive histone H3 lysine 9 trimethylation (H3K9me3) mark. Increasing H3K9me3 levels by histone demethylase inhibition led to cell death in GICs but not in their differentiated counterparts. The induction of apoptosis was accompanied by a loss of the activating H3 lysine 9 acetylation (H3K9ac) modification and accumulation of DNA damage and downregulation of DDR genes. Upon knockdown of histone demethylases KDM4C and KDM7A both differentiation and DNA damage was induced. Thus, the H3K9me3-H3K9ac equilibrium is crucial for GIC viability and represents a chromatin feature that can be exploited to specifically target this tumor subpopulation.

  Study EGAS00001003750

• The Egyptian Collaborative Cardiac Genomics (ECCO-GEN) Project: Defining a Healthy Volunteer Cohort

  The integration of comprehensive genomic and phenotypic data from diverse ethnic populations offers unprecedented opportunities towards advancements in precision medicine and novel diagnostic technologies. Current reference genomic databases are not representative of the global human population, making variant interpretation challenging, especially in underrepresented populations such as the North African population. To address this, the Egyptian Collaborative Cardiac Genomics (ECCO-GEN) Project launched a study comprising 1000 individuals free of cardiovascular disease (CVD). Here, we present the first 391 Egyptian healthy volunteers (EHVols) recruited to establish a pilot phenotyped control cohort. All individuals underwent detailed clinical investigation, including cardiac MRI, and were sequenced using a targeted panel of 174 genes with reported roles in inherited cardiac conditions (ICC). We identified 1,262 variants in 27 cardiomyopathy genes of which 15.1% were not captured in current global and regional genetic reference databases (here: gnomAD and Great Middle Eastern (GME) Variome). The ECCO-GEN project aims at defining the genetic landscape of an understudied population and providing individual-level genetic and phenotypic data to support future studies in CVD and population genetics.

  Study EGAS00001004434

• Comprehensive Genomic Characterization of Gene Therapy-Induced T-cell Acute Lymphoblastic Leukemia (H007)

  Six out of ten patients in a hematopoietic stem cell gene therapy (GT) trial for Wiskott-Aldrich syndrome (WAS) developed T-cell acute lymphoblastic leukemia (T-ALL) associated with gamma-retroviral vector integration at the LMO2 locus. We hypothesized that detailed molecular analysis of T-ALL driven by temporally defined first deregulation of LMO2 might offer valuable insights into the pathogenesis of GT-associated and sporadic T-ALL (HIPO project 007). In all six patients whole-genome and transcriptome sequencing demonstrated that in addition to oncogenic chromosomal translocations involving the T-cell receptor loci, retrovirally induced leukemias faithfully recapitulated secondary genomic events observed in sporadic T-ALL. Multiple genetic events culminated in the development of a rapidly proliferating leukemic clone and onset of clinical manifestation at 1.3 to 5 years after infusion of the gene corrected transplant. These genetic alterations affected NOTCH1 and PI3K signaling, cell cycle regulation as wells as T-cell transcription factors LEF1 and TCF1. Two of the six cases displayed a phenotype reminiscent of early immature T-ALLs, and lacked additional T-ALL typical alterations. Our analysis shows that insertional mutagenesis involving the LMO2 locus triggers T-ALL development due to diverse genetic alterations in large parts, but not exclusively, in known T-ALL driver genes, demonstrating the molecular diversity of GT-associated T-ALL.

  Study EGAS00001003870