30 results for "study_type:"exome sequencing" AND repository:dbGaP"

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• Inherited Defect in ST6GalNAc1 Reveals Roles of Sialylation in Intestinal Homeostasis

  We have conducted a study of patients with unique mutations in the gene <a href="https://www.ncbi.nlm.nih.gov/gene/55808" target="_blank">ST6GALNAC1</a> that encodes the protein ST6GALNAC1 (ST6). Exome sequencing was used to screen worldwide inflammatory bowel disease cohorts, which identified human loss of function mutations of ST6 in individual patients. The affected patients had very early onset (&lt; 6 years old) inflammatory bowel disease. A comprehensive investigation of these gene mutations through <i>in vivo</i> and <i>in vitro</i> experiments revealed that decreased sialylation caused defective mucus proteins and congenital inflammatory bowel disease.

  Study phs002598

• RB1 Loss Triggers Dependence on ESRRG in Retinoblastoma

  <p>Retinoblastoma (Rb) is a deadly childhood eye cancer that is classically initiated by inactivation of the RB1 tumor suppressor. Clinical management continues to rely on nonspecific chemotherapeutic agents that are associated with treatment resistance and toxicity. Here, we analyzed whole exomes from primary Rb tumors to identify novel Rb dependencies. Several recurrent genomic aberrations implicate estrogen-related receptor gamma (ESRRG) in Rb pathogenesis. ESRRG is an essential mediator of hypoxic adaptation and cell survival in retinoblastoma, representing a promising new therapeutic target.<br></p>

  Study phs002859

• Combined Targeting of CDK4/6 and HER2 Signaling in Orthotopic Patient-Derived Xenografts of HER2-Positive Breast Cancer Brain Metastases

  <p>Patients with metastatic HER2-positive (HER2+) breast cancer will frequently develop brain metastases (BCBMs). Here, we report that p16INK4A, a tumor suppressor, is deficient in the majority of HER2+ BCBMs. Furthermore, p16INK4A deficiency, as measured by protein immunohistochemistry, can be a predictive marker associated with response to combined treatment with tucatinib and abemaciclib in our orthotopic patient-derived xenografts (PDXs) models of HER2+ BCBMs. Our findings provide the rationale for a biomarker-driven clinical trial of combined treatment with CDK4/6- and HER2-targeted agents for patients with HER2+ BCBM.&nbsp;&nbsp;</p>

  Study phs002482

• Lineage Plasticity and Immune Cell Heterogeneity Are Coordinately Dysregulated Through Changes in FOXA1 Expression in Bladder Cancers with Squamous Differentiation

  We performed whole exome sequencing (WES) of paired, macrodissected regions of urothelial carcinoma (UC), not otherwise specified (NOS-UC) and squamous differentiation (SqD) from 21 bladder tumors in which distinct and separable NOS-UC and SqD regions were present (total 42 exomes, in addition to matched normal exomes). Mean tumor mutational burden (TMB) was higher in the SqD versus the NOS-UC regions. Consistent with the higher TMB, the SqD regions also had a higher neoantigen burden than the patient-matched NOS-UC regions. The SqD regions also exhibited higher karyotypic complexity with a higher median ploidy relative to the paired NOS-UC regions. Phylogenetic analysis of the WES data confirmed that the morphologically distinct regions of all 21 tumors arose from a shared precursor with a median of 68 (range 16 &#8211; 852) non-synonymous mutations shared between the NOS-UC and SqD regions, and the overall data were indicative of early branched evolution. As whole exome sequencing did not identify a shared mutational alteration or genomic signature unique to the SqD or NOS-UC components, we therefore performed expression profiling of separable SqD and NOS-UC regions of 12 bladder tumors from the WES cohort with RNA quality sufficient for whole transcriptome RNA-sequencing (RNAseq, total of 24 regions). Based on centroid clustering analysis of expression data, all 12 regions of SqD were basal-squamous subtype based on the TCGA molecular classification schema. Notably, 8 of the NOS-UC regions were also basal-squamous subtype, with only four pairs exhibiting discordant transcriptional subtypes (three NOS-UC regions were luminal-infiltrated, one luminal-papillary). To better quantify differences in the transcriptional profiles of the paired NOS-UC and SqD regions, we used single sample gene set enrichment analysis (ssGSEA) to assess for enrichment of luminal or basal-squamous gene expression. ssGSEA analysis revealed that the SqD regions expressed higher levels of basal-squamous genes based on the BASE47 gene set and UPK/KRT gene sets; whereas the matched NOS-UC regions expressed higher levels of luminal genes. These differences in the levels of expression of basal and luminal genes were observed even in cases in which both the NOS-UC and SqD regions were basal-squamous subtype based the TCGA molecular classification schema. Exomes from eight patients in this study have previously been deposited in dbGaP: accession number <a href="https://www.ncbi.nlm.nih.gov/gap/advanced_search/?TERM=phs001783" target="_blank">phs001783</a> as part of the study "Exome Recapture and Sequencing of Prospectively Characterized Clinical Specimens From Cancer Patients".

  Study phs002357

• Germline and Somatic Genetic Landscape of Pediatric Rhabdomyosarcoma

  Dynamic approaches that integrate population-based research and molecular biology are needed to explain the mechanisms underlying pediatric rhabdomyosarcoma (RMS) and to determine novel prevention strategies. RMS, the most common soft-tissue sarcoma in children and adolescents, has one of the poorest 5-year survival rates among all pediatric cancers (less than 65%). One of the strongest risk factors for RMS is having a cancer predisposition syndrome. The syndromes that are most commonly seen among those with RMS are Li-Fraumeni, neurofibromatosis type 1, Costello, Noonan, and DICER1. Based on smaller clinic-based studies, only about 7% of RMS cases are thought to be associated with the genes responsible for these syndromes. However, there have been no population-based assessments to support this estimate. Even in the most recent large-scale evaluations of germline mutations in predisposition genes among children with cancer, very few RMS cases were included (43 cases). Furthermore, no distinctions were made between the major histologic subtypes of RMS: embryonal (eRMS) and alveolar (aRMS), which display differences in terms of age distribution, incidence, and cytogenetics. For instance, nearly 80% of alveolar cases are driven by a chromosomal translocation between either PAX3 or PAX7 and FOXO1, whereas these fusions are not seen in embryonal cases. In fact, RMS research is shifting from categorization based on histology to fusion status (eRMS is overwhelmingly fusion-negative). Another limitation in previous studies has been the inability to evaluate the frequency of de novo germline mutations (DNMs) in cancer predisposition genes due to the absence of any well-characterized cohorts of RMS case-parent trios. Therefore, a major gap in our understanding of the role of cancer predisposition in pediatric RMS that limit translational impact is there have been no population-based assessments to determine the true impact of these mutations on pediatric RMS, which limits clinical sequencing guidelines and surveillance protocols in these children.<br><br>Overall Project Strategy: The objective of this project is to advance our understanding of the relationship between cancer predisposition genes and pediatric RMS. Our central hypotheses are: 1) mutations in cancer predisposition genes are more common than expected in children with RMS; and 2) children with fusion-negative tumors have a higher burden of germline mutations than those with fusion-positive tumors. The framework for this study relies on &gt;600 well annotated samples collected from newly diagnosed RMS patients and stored in the Children&#8217;s Oncology Group (COG) Biopathology Center.<br><br>

  Study phs002304

• Novel Gene-Environment Regulatory Circuit in Chamber-Specific Growth of Perinatal Heart

  <p>We report a case of hypertrophic cardiomyopathy and lactic acidosis in a 3-year-old female. Cardiac and skeletal muscle biopsies exhibited mitochondrial hyperplasia with decreased complex VI activity. Whole exome sequencing identified compound heterozygous variants, p.Arg333Trp and p.Val119Leu, in <a href="https://www.ncbi.nlm.nih.gov/gene/10102" target="_blank">TSFM</a>, a nuclear gene that encodes a mitochondrial translation elongation factor, resulting in impaired oxidative phosphorylation and juvenile hypertrophic cardiomyopathy.</p>

  Study phs002725

• Intercepting Progression from Pre-Invasive to Invasive Lung Adenocarcinoma

  <p>An improved understanding of the biology of lung cancer is needed to intercept the disease at an early point in its progression. In this project we have used multidimensional methods to profile the tumor microenvironment (TME) and to determine the crosstalk between cancer cells and the TME in pre-invasive to invasive human lung non-solid adenocarcinomas. Comparative analysis of the cellular and molecular events associated with the distinct histological stages will lead to identification of the critical events triggering progression and thereby identify targets to intercept disease progression. The data being submitted represents the genomic profiles of patient samples with pre-invasive and invasive human lung adenocarcinomas.</p>

  Study phs002818

• Genetic Analysis of Limb Malformation Disorders: Miller Syndrome Sequencing Study (LMD-MS)

  <p>The overall goal of this project is to investigate the etiology and pathogenesis of malformations (i.e., birth defects) of the limb, concentrating on abnormalities of limb patterning such as limb deficiency/duplications and multiple congenital contractures.</p> <p>The exome sequences of two siblings and two unrelated individuals were obtained by massively parallel DNA sequencing. The four individuals were affected with Miller syndrome (OMIM: <a href="http://www.ncbi.nlm.nih.gov/omim/263750">263750</a>).</p> <p>Additionally, the whole-genome sequences of a family of four were obtained with the method of Complete Genomics Incorporated (CGI). The two offspring were both affected with Miller syndrome and is the same sibling pair mentioned previously from whom exome sequences were also obtained.</p>

  Study phs000244

• Dissecting Cell Composition and Drug Sensitivity in Human Adenoid Cystic Carcinomas (ACCs)

  <p>The study reports the results of single-cell RNA sequencing (scRNA-seq), RNA sequencing (RNA-seq), and whole-exome sequencing (WES) experiments performed on malignant cells isolated by flow cytometry from seven patient-derived xenograft (PDX) lines established from human Adenoid Cystic Carcinomas (ACCs). Of these seven lines, five are characterized by well differentiated histology (ACCX5M1, ACCX6, ACCX14, ACCX22, SGTX6) and two by solid histology (ACCX9, ACCX11). Analysis by scRNA-seq of the well-differentiated PDX line ACCX22 led to identification of cell-surface markers (CD49f, KIT) that enabled the differential purification of the two major cellular components contained in well-differentiated ACCs: myoepithelial-like (CD49f-high/KIT-negative) and ductal-like (CD49f-low/KIT-positive) cells. The study reports the analysis by RNA-seq and WES of purified preparations of myoepithelial-like and ductal-like cells from well-differentiated PDX lines (ACCX5M1, ACCX6, ACCX14, ACCX22, SGTX6) and of ductal-like (CD49f-low/KIT-positive) cells from solid PDX lines (ACCX9, ACCX11).</p>

  Study phs002764

• Longitudinal Studies of Patients with Familial Platelet Disorder with Associated Myeloid Malignancy (FPDMM)

  <p>FPDMM (<a href="https://www.omim.org/entry/601399?search=601399&amp;highlight=601399" target="_blank">OMIM #601399</a>) is a rare autosomal dominant disease characterized by defective megakaryocytic development, thrombocytopenia, platelet functional defects, and a life-long risk of developing hematological malignancies. FPDMM is caused by germline mutations in the <i><a href="https://www.ncbi.nlm.nih.gov/gene/?term=861" target="_blank">RUNX1</a></i> gene, which encodes a master regulator of hematopoiesis. The overall lifetime risk of hematological malignancies in FPDMM patients is 35 - 45%. It is hypothesized that mutations in other genes cooperate with the germline <i>RUNX1</i> mutations for leukemia development. However, it is not clear which genes need to be mutated for leukemia to develop and which biomarkers or clinical tests can be used to predict which patients will progress to leukemia. Likewise, there are no treatments and/or preventative measures that can reduce or stop disease progression except for stem cell transplantation, which is not available for all patients and may be associated with significant complications. </p><p>To address these questions, we launched a longitudinal natural history study of patients associated with <i>RUNX1</i> germline mutations at the NIH Clinical Center in early 2019 (Trial Registration ID: <a href="https://clinicaltrials.gov/ct2/show/NCT03854318" target="_blank">NCT03854318</a>). The goals of this study are to: (1) perform comprehensive longitudinal phenotyping of FPDMM patients to document the full spectrum of both hematopoietic and non-hematopoietic manifestations of the disease; and (2) perform extensive genomic analyses of FPDMM patient samples to identify cooperating genomic variants, which may confer growth advantage that leads to clonal expansion of affected hematopoietic cells that may serve as the precursor to malignancies. </p><p>The data available through dbGaP include exome sequencing and RNA-seq data from these patients. Diverse germline mutation types were identified in the <i>RUNX1</i> gene, including splice site mutations and large deletions, in addition to nucleotide substitutions and small indels. Somatic mutations, especially in genes associated with clonal hematopoiesis of indeterminate potential (CHIP), were found in a substantial proportion of FPDMM patients who were leukemia-free. The findings suggest that the genomes in these patients are prone to somatic mutations and monitoring the dynamic changes of these somatic mutations prospectively may provide a way to predict progression to malignancies. </p><p> </p><p> </p>

  Study phs003075