Search Results - EGA European Genome-Phenome Archive

Defining T cell States Associated with Response to Checkpoint Immunotherapy in Melanoma

Checkpoint blockade therapy using antibodies targeting CTLA4, PD1 or PDL1 have changed the way cancer patients with advanced disease are being treated, as evident by their FDA approval in a wide variety of malignancies, and their ability to induce high response rates when compared to conventional therapies (e.g. chemotherapy). However, even in melanoma, despite the high response rate, most patients are refractory to therapy or acquire resistance in 10-12 months. To identify key immunological elements coupled with response or resistance to checkpoint immunotherapy, we performed an unbiased analysis on 16,291 CD45+ immune cells from 32 patients (48 samples) treated with checkpoint therapy (anti-PD1=37; anti-PD1/CTLA4=11), using single cell transcriptomics. Initial unsupervised clustering of all CD45+ cells identified 11 clusters. When examining the association of these clusters with clinical outcome, we found that two clusters (B-cells, p=0.005; memory T-cells, p=0.03) were significantly enriched in responder lesions while 4 clusters (monocytes/macrophages, p=0.003; dendritic cells, p=0.015; exhausted CD8+ T-cells, p=0.005; and exhausted/cell-cycle lymphocytes, 1.3x10-5) are enriched in non-responder lesions. Next, by leveraging our unbiased single cell approach, we identified not only clusters but also specific markers associated with either responder lesions (PLAC8, LTB, LY9, SELL, TCF7, IGKC and CCR7) or non-responder ones (CCL3, CD38, HAVCR2, ENTPD1 and WARS), many of which were not previously reported to be associated with clinical outcome to checkpoint therapy. Due to the importance of CD8+ T-cells in controlling tumors, the significant association of T-cell states with clinical outcome, and their high abundance in melanoma tumors, we next focused our analysis on CD8+ T-cells and identified 2 main clusters CD8_G (with increased expression of genes linked to memory) and CD8_B (enriched for genes linked to cell dysfunction), that were significantly enriched in responder (CD8_G, p=1.4x10-6) and non-responder (CD8_B, p=0.005) lesions, respectively. Since cells with both states coexist in each of the responder and non-responder lesions, we decided to calculate the ratio between the number of cells in these 2 clusters and observed a significant separation between responders (CD8_G/CD8_B>1) and non-responders (CD8_G/CD8_B<1) when looking at all samples, baseline or post samples separately. Similar results were detected when looking at the expression of a single transcription factor, TCF7, in CD8 T-cells in an independent cohort (n=43) using a simple immunofluorescence assay. Additionally, we validated the identity and function of some of the newly identified cell states as well as their epigenetic landscape, and found that cells expressing the inhibitory molecules CD39 and TIM3, on top of being enriched in non-responder lesions, are likely to play a crucial role in T-cell exhaustion in melanoma. Collectively, our study provides extensive unbiased data in human tumors for discovery of predictors and therapeutic targets to checkpoint immunotherapy.

Study phs001680

Robust detection of translocations in lymphoma FFPE samples using Targeted Locus Capture-based sequencing

Chromosomal translocations with immunoglobin (IG) loci are the classic drivers in a large subset of B-cell lymphomas. Detection of these translocations is important for confirmation of diagnosis and for prognosis and therapy decisions. Currently, molecular diagnosis of translocations in lymphomas is not addressed well by Next Generation Sequencing (NGS). The standard method for detection of translocations is Fluorescence In Situ Hybridization (FISH), which is labor-intensive, and can be difficult to interpret. There is a need for a robust technology that can be standardized. Targeted Locus Capture (TLC) selectively enriches and sequences entire genes based on the crosslinking of physically proximal sequences, and thereby enables complete sequencing of genes of interest, including detection of large structural variants. Because the technology is based on the crosslinking and fragmenting of DNA, it has particular advantages in the analysis of Formalin-Fixed, Paraffin-Embedded (FFPE) samples, in which DNA is inherently crosslinked and fragmented. In order to validate the FFPE-TLC technology as a novel approach for translocation detection in lymphoma samples, we have developed a panel assay containing genes with frequent translocations (MYC, BCL2, BCL6, IG loci). With this assay we have analyzed >140 lymphoma and control FFPE samples of variable input amounts and qualities that had previously been analyzed with FISH, and a subset also with standard targeted NGS. Good concordance with FISH results was observed for both translocation positive and negative samples. In 10 cases for which FFPE-TLC detected a relevant fusion and FISH had been called negative, discordance could be explained by higher sensitivity of FFPE-TLC or by inconclusive FISH results. In a specific case, FFPE-TLC detected a small-distance rearrangement on chromosome 3 that caused a BCL6 fusion but led to insufficient and therefore undetectable break-apart with FISH. Secondly, the FFPE-TLC approach was tested on a set of 19 B-cell lymphoma FFPE samples that had previously been analyzed using standard targeted NGS and FISH and was enriched for discordant results between these methods. FFPE-TLC-based NGS enables more robust translocation calling as the detection relies on broad sequencing coverage across the translocation partner rather than on breakpoint sequences only. In 3 cases, FFPE-TLC could proof false negative calls in standard targeted NGS due to breakpoints located in regions difficult to capture or to sequence. In 1 case, standard targeted NGS had made a false positive call on a breakpoint sequence that was shown to be caused by a small insertion rather than a genuine translocation. This study shows that FFPE-TLC promises to be a robust alternative for FISH analysis and standard targeted NGS procedures in lymphoma diagnostics and possibly in other cancers with frequent structural variants. The FFPE-TLC approach enables a single, DNA-based NGS test detecting both small mutations and translocations.

Study EGAS00001004760

Charles R. Bronfman Institute for Personalized Medicine (IPM) BioBank Genome Wide Association Study of Cardiovascular, Renal and Metabolic Phenotypes

The Institute for Personalized Medicine (IPM) Biobank Project is a consented, EMR-linked medical care setting biorepository of the Mount Sinai Medical Center (MSMC) drawing from a population of over 70,000 inpatients and 800,000 outpatient visits annually. MSMC serves diverse local communities of upper Manhattan, including Central Harlem (86% African American), East Harlem (88% Hispanic Latino), and Upper East Side (88% Caucasian/white) with broad health disparities. IPM Biobank populations include 28% African American (AA), 38% Hispanic Latino (HL) predominantly of Caribbean origin, 23% Caucasian/White (CW). IPM Biobank disease burden is reflective of health disparities with broad public health impact: average body mass index of 28.9 and frequencies of hypertension (55%), hypercholesterolemia (32%), diabetes (30%), coronary artery disease (25%), chronic kidney disease (23%), among others. Biobank operations are fully integrated in clinical care processes, including direct recruitment from clinical sites, waiting areas and phlebotomy stations by dedicated Biobank recruiters independent of clinical care providers, prior to or following a clinician standard of care visit. Recruitment currently occurs at a broad spectrum of over 30 clinical care sites. Minorities are strikingly underrepresented in GWAS, including Coronary Artery Disease (CAD) and Chronic Kidney Disease; multigenic genetic risk scores for CAD have been recently validated in European ancestry populations, but not in AA or HL populations. Several important opportunities exist for extending additional GWAS to minority populations with a shared risk spectrum of CAD and CKD. For example, progressive CKD is a major and independent risk factor for CVD with an inverse relationship between estimated GFR (eGFR), and risk for mortality and cardiovascular events. This increased risk is only partially explained by the prevalence of cardiovascular risk factors among these patients. We conducted a GWAS of CAD and CKD related phenotypes in IPM Biobank with the primary objective to explore the genetics of overlapping CAD and CKD predominantly in minority populations characterized by increased risk.

Study phs000388

RNAseq data to study PRPF6 regulated splice forms in colon cancer cell lines

Alternative splicing plays critical roles in differentiation, development, and cancer (Pettigrew et al., 2008; Chen and Manley, 2009). The recent identification of specific spliceosome inhibitors has generated interest in the therapeutic potential of targeting this cellular process (van Alphen et al., 2009). Using an integrated genomic approach, we have identified PRPF6, an RNA binding component of the pre-mRNA spliceosome, as an essential driver of oncogenesis in colon cancer. Importantly, PRPF6 is both amplified and overexpressed in colon cancer, and only colon cancer cells with high PRPF6 levels are sensitive to its loss. Our data clearly point to an important role for PRPF6 in colon cancer growth and suggest that a better understanding of its role in alternative splicing in colon cancer is warranted. To determine the specific alternative splice forms that PRPF6 regulates in colon cancer, we plan three experiments: 1. The first involves knocking down expression of PRPF6 in two different cancer cell lines with 3 different siRNAs, and then completing RNA-seq to determine the gene expression changes that occur relative to a non-targeting control siRNA. Because of the role for PRPF6 in pre-mRNA splicing, we especially want to quantify the changes in splice-specific forms of all genes genome-wide to identify genes whose splicing is altered upon PRPF6 knockdown. 2. The second involves immunoprecipitating PRPF6 from two different cancer cell lines and isolating any RNA that is bound to PRPF6, since PRPF6 is an RNA-binding protein. We then want to carry out RNA-seq to identify which RNA molecules co-immunoprecipitated with PRPF6. This will help us determine possible functions for PRPF6 in regulating colon cancer growth. 3. The third involves overexpressing PRPF6 in cell lines and then carrying out RNA-seq to identify any changes in splice-specific gene expression. This will allow us to determine whether increased PRPF6 expression is sufficient to drive alternative splicing changes.

Study EGAS00001000761

A Comprehensive Catalogue of Somatic Mutations from a Human Cancer Genome

We have carried out complete sequencing of the genome of the human male maligant melanoma cell line COLO-829 using the Illumina Genome Analyzer II. We generated a sequencing library with a median insert size of ~200 bp following random fragmentation and gel fractionation of the genomic DNA. We sequenced 75 bases from both ends of these templates to cover the COLO-829 genome to an average depth of more than 40x. We have carried out purity-filtering (PF) to remove mixed reads, where two or more different template molecules are close enough on the surface of the flow-cell to form a mixed or overlapping cluster. No other filtering of the data has been carried out prior to submission. We have also submitted sequence data for a lymphoblastoid control cell line COLO-829BL from the same individual.

Study EGAS00000000052

Massive Genomic Rearrangment Acquired in a Single Catastrophic Event During Cancer Development

Cancer is driven by mutation. Using Agilent exome hybridisation capture and Illumina GA massively parallel sequencing technology, we aim to sequence ~1600 microRNAs plus the protein coding genome of 25 matched human renal cancer samples. Bespoke algorithms are being developed to identify the somatically acquired point mutations, insertions and deletions in these samples. This project will give unprecedented insights into mutational processes, cellular repair pathways and gene networks associated with renal cancer development.Agilent whole exome hybridisation capture will be performed on genomic DNA derived from 25 renal cancers and matched normal DNA from the same patients. Three lanes of Illumina GA sequencing will be performed on the resulting 50 exome libraries and mapped to build 37 of the human reference genome to facilitate the identification of novel cancer genes.

Study EGAS00000000029

Clonally heritable gene expression imparts a layer of diversity within cell types

Cell types can be classified according to shared patterns of transcription. Non-genetic variability among individual cells of the same type has been ascribed to stochastic transcriptional bursting and transient cell states. Using high coverage single cell RNA profiling, we asked whether long-term, heritable differences in gene expression can impart diversity within cells of the same type. Studying clonal human lymphocytes and mouse brain cells, we uncovered a vast diversity of heritable gene expression patterns among different clones of cells of the same type in vivo. We combined chromatin accessibility and RNA profiling on different lymphocyte clones to reveal thousands of regulatory regions exhibiting interclonal variation which could be directly linked to interclonal variation in gene expression. Our findings identify a source of cellular diversity, which may have important implications for how cellular populations are shaped by selective processes in development, aging and disease.

Study EGAS50000000161

SCANDARE MACARON

Among gynecological cancers, high-grade serous ovarian cancer has the highest prevalence and more than 75% of patients have advanced stage at diagnosis with a 5-year survival of 40%. When the initial complete surgical removal is not possible (60% of patients), an interval surgery can be considered after three to four cycles of neoadjuvant chemotherapy to reduce the tumor mass. However, in approximately 50% of cases the tumor has little or no response to neoadjuvant chemotherapy. Therefore, identification of potential drug targets, biomarkers and/or pathways whose modulation can help in the prevention, interception, or curing of the disease is essential to address the unmet need. Therefore, MACARON project aims to address these issues through the identification of shared neoantigens arising out of somatic alterations and aberrant transcriptional programs in ovarian cancer DNA/RNA datasets.

Study EGAS50000000145

RNA-seq data for study 'Smoking-dependent expression alterations in nasal epithelium reveal immune impairment linked to germline variation and lung cancer risk.'

RNA-seq data from nasal and bronchial tissues in 649 subjects, many with lung cancer. Lung cancer is the leading cause of cancer-related death in the world. In contrast to many other cancers, a direct connection to lifestyle risk in the form of cigarette smoke has long been established. More than 50% of all smoking-related lung cancers occur in former smokers, often many years after smoking cessation. Despite extensive research, the molecular processes for persistent lung cancer risk are unclear. CT screening of current and former smokers has been shown to reduce lung cancer mortality by up to 26%. To examine whether clinical risk stratification can be improved upon by the addition of genetic data, and to explore the mechanisms of the persisting risk in former smokers, we have analyzed transcriptomic data from accessible airway tissues of 487 subjects. We developed a model to assess smoking associated gene expression changes and their reversibility after smoking is stopped, in both healthy subjects and clinic patients. We find persistent smoking associated immune alterations to be a hallmark of the clinic patients. Integrating previous GWAS data using a transcriptional network approach, we demonstrate that the same immune and interferon related pathways are strongly enriched for genes linked to known genetic risk factors, demonstrating a causal relationship between immune alteration and lung cancer risk. Finally, we used accessible airway transcriptomic data to derive a non-invasive lung cancer risk classifier. Our results provide initial evidence for germline-mediated personalised smoke injury response and risk in the general population, with potential implications for managing long-term lung cancer incidence and mortality.

Dataset EGAD50000000333

UK Biobank whole cohort directly genotyped and imputed data (~500,000 participants)

Genotype data is available for all 500,000 participants in the UK Biobank cohort. Genotyping has been performed using the Affymetrix UK BiLEVE Axiom array on an initial 50,000 participants and the remaining 450,000 participants have been genotyped using the Affymetrix UK Biobank Axiom® array. The two arrays are extremely similar (with over 95% common content).Quality control and imputation (to over 90 million SNPs, indels and large structural variants) has been performed by a collaborative group headed by the Wellcome Trust Centre for Human Genetics.The following data are available:* A clean set of QC’ed genotype calls* Confidence values that a genotype call is correct* Intensity data to generate cluster plots* Extensive QC information regarding SNPs and samples including SNP metrics, batch effects, population structure and relatedness* Imputed dataFor further information, please refer to the UK Biobank website

Study EGAS00001002399

Polygenic Risk Score for the Prediction of Breast Cancer Is Related to Lesser Terminal Duct Lobular Unit Involution of the Breast

The Susan G. Komen Tissue Bank (KTB) at the Indiana University Simon Cancer Center is an annotated biobank, which has recruited healthy women who provided demographic, lifestyle, and cancer-related information via self-administered questionnaire, blood samples and normal breast tissues. H&E slides of the normal breast tissues were scanned for image analysis and a pathologist measured the number of terminal duct lobular units (TDLUs) ("TDLU count"). The acini count per TDLU was quantified using the TDLU analyzer software. In this analysis, we computed the recently developed polygenic risk score (PRS) based on 313 common variants for the prediction of breast cancer and related this PRS to TDLU count and acini count per TDLU. We did this for the overall PRS, the ER-positive PRS and the ER-negative PRS.

Study phs002062

HuBMAP: KULMAP - Human Kidney, Urinary Tract, and Lung Mapping Center

The major goal of the Human Kidney, Urinary Tract, and Lung Mapping Center (KULMAP) is to generate multi-omic and spatially resolved molecular anatomical maps of the human bladder, ureter and kidneys (BUKMAP) and the lung airways and parenchyma (LAPMAP) at a single cell resolution. This entails sequencing of the transcriptomes and epigenomes of dissociated single cells in a massively parallel manner. These profiles will then inform on highly multiplexed RNA in situ imaging for spatial mapping of hundreds of molecular targets in the tissue sections, at a subcellular resolution. These spatial molecular maps will serve as scaffolds for computational registration of cell types and the associated transcriptome/chromatin maps to the tissue space. The combination of sequencing single dissociated cells and multiplexed in situ mapping will allow the construction of detailed spatial maps for these large organs.

Study phs002249

SU2C-MARK Lung Cancer Consortium - Checkpoint Blockade Response Project

Immune checkpoint inhibitors have become a critical part of the armamentarium against advanced Non-Small Cell Lung Cancer (NSCLC). While early studies have identified Tumor Mutation Burden (TMB) and PD-L1 staining as important biomarkers of response, they remain imperfect predictors. Here we describe a multi-institutional effort as part of the SU2C-MARK Lung Cancer Consortium in which Whole Exome Sequencing (WES) - and in select cases, RNA sequencing – was performed on a large collection of NSCLC samples prior to immune checkpoint blockade therapy, along with matched clinical response data following therapy. (Profiling of a small number of on- or post-treatment samples was also performed.) We anticipate this dataset to be of high value for the development of a deep understanding of the molecular determinants of immune checkpoint blockade response as well as the discovery of novel biomarkers.

Study phs002822

Rapid Acceleration of Diagnostics - Digital Health Technologies (RADx-DHT): NIH Digital Health Solutions for COVID-19: IBM Covid19 Contact Tracing and Data Exchange Tools

The goal of this project is to develop both contact tracing and secure data exchange tools. The contact tracing solution securely combines data from a variety of sources (including manual self-report data and mobile device surveys) to enable tracing of contacts with individuals that have tested positive for COVID-19 or have been exposed to COVID-19. The data exchange solution is a secure mechanism that empowers users to control the data they share in the course of their return to work, including the ability to provide a verifiable health status claim. These tools are being used by an employer to evaluate the risk of allowing individuals to return to normal activities, and also the ability to trace user contact with individuals diagnosed with or suspected of having contracted COVID-19. DOI: https://rapids.ll.mit.edu/10.57895/h0an-m559

Study phs002516

Anorexia Nervosa Genetics Initiative (ANGI)

The Anorexia Nervosa Genetics Initiative (ANGI) is an international collaboration that recruited individuals with a lifetime history of anorexia nervosa from the United States (US), Australia/New Zealand (ANZ), Sweden (SE), and Denmark (DK). Matched controls, with no history of eating disorders, were also recruited from the US, SE, and DK. Recruitment avenues included national registers (SE, DK), treatment centers (US, ANZ, SE, DK), and social and traditional media (US, ANZ, SE). Participants provided blood samples and clinical information. Diagnoses were based on DSM-IV or ICD-10 criteria (amenorrhea was not required). Genotype data are available for 12,918 participants. *NOTE: Denmark data cannot be shared openly but require prior and individual permission by the data owner: The Head of the National Center for Register Based Research Aarhus, DK. Genotyping of samples from Denmark was completed using the Illumina PsychArray (data not supplied).

Study phs001541

Genome-Wide Analysis of Splenic Marginal Zone Lymphoma

Splenic Marginal Zone Lymphoma (SMZL) is a B-cell malignancy of unknown pathogenesis and thus orphan of targeted therapies. By integrating whole-exome sequencing and copy-number analysis of 8 paired tumor-normal DNAs from patients with SMZL, we show that the typical SMZL exome carries ~30 genetic alterations. Targeted resequencing of selected candidates in an extended panel of 40-117 samples revealed activating mutations of NOTCH2, a gene required for marginal-zone (MZ) development, as the most frequent and SMZL-specific lesion, accounting for approximately 20% of cases. Additional altered genes suggest that deregulation of signaling pathways normally involved in MZ development (NOTCH, NF-kappa B, and B-cell receptor) represents a critical event in SMZL pathogenesis. These findings have direct implications for the treatment of SMZL patients since drugs are available which can target NOTCH as well as other pathways deregulated in this disease.

Study phs000502

DAXX restoration suppresses alternative lengthening of telomeres in ATRX wild-type cells

Many tumors maintain chromosome ends through a telomerase-independent, homologous recombination based mechanism called alternative lengthening of telomeres (ALT). While ALT occurs in only a subset of tumors, it is strongly associated with mutations in the genes encoding components of the histone H3.3 chaperone complex, ATRX and DAXX. To date the mechanistic role of ATRX and particularly DAXX mutations in potentiating ALT remains poorly understood. We identify an osteosarcoma cell line, G292, with a unique chromosomal translocation resulting in loss of DAXX function, while retaining functional ATRX. Using this distinctive resource, we demonstrate that introduction of wild type DAXX suppresses the ALT phenotype and restores localization of the ATRX/DAXX complex to PML bodies. This provides the first direct molecular evidence that ongoing DAXX deficiency is essential for maintenance of the ALT phenotype and highlights the potential for therapeutic targeting of this oncogenic pathway.

Study phs001495

Profiles of Extracellular RNA in Cerebrospinal Fluid and Plasma from Subarachnoid Hemorrhage Patients

Brain injury resulting from hemorrhagic stroke is clinically challenging to manage and results in high rates of morbidity and mortality. The pathophysiology of brain damage resulting from aneurysmal subarachnoid hemorrhage (aSAH) is largely unknown, and methods to treat and monitor patients are variable with no meaningful correlations to patient outcome. Prediction of patient risk for serious neurological complications is currently a significant clinical obstacle. An extracellular RNA (exRNA) biomarker to predict onset and severity of brain damage would improve patient outcomes. We sequenced plasma and CSF samples from adult patients with SAH. Samples were collected from post bleed day 1 to day 7. Total exRNA was isolated from each sample. In addition, we prepared a subset of 140 CSF samples, isolating the RNA contained within extracellular vesicles and vesicle-depleted biofluid.

Study phs001759

National Human Genome Research Institute Tumor Sequencing Project (TSP) - Lung Adenocarcinoma

The Tumor Sequencing Project (TSP) Consortium is a collaboration among participants at the Baylor College of Medicine Human Genome Sequencing Center, the Broad Institute Genome Sequencing Platform, the Dana Farber Cancer Institute, the Memorial Sloan-Kettering Cancer Center, the Genome Sequencing Center and Siteman Cancer Center at Washington University, the M.D. Anderson Cancer Center and the University of Michigan Medical Center. The TSP Part A will pilot approaches to large-scale identification of genomic changes in tumors by sequencing the exonic regions of 623 genes in 188 specimens of adenocarcinoma of the lung, as well as using high density SNP genotyping arrays for high resolution identification of changes in chromosomal copy number. The TSP Part B will pilot approaches to tumor characterization of lung adenocarcinoma samples using next-generation sequencing technologies and benchmark those results against Part A data generated with ABI3730 instruments.

Study phs000144

RNAseq Transcriptomic Analyses of European Ancestry Samples in MGS Dataset

Schizophrenia is a common and severe psychotic disorder. While some common SNPs and rare copy number variants have been identified as being significantly associated with disease risk, the biological mechanisms remain undefined. To identify gene expression abnormalities in schizophrenia, we generated whole-genome gene expression profiles using RNAseq on lymphoblastoid cell lines from schizophrenia cases and controls of European ancestry. Subsets of these data have been used in three studies: (1) gene expression outliers (extreme tails of the distribution of transcript expression values) in 634 cases and 713 controls (PMID: 26022996); (2) baseline differential gene expression by affection status in 529 cases and 660 controls (PMID: 28418402); and (3) baseline versus dopamine stimulated differential gene expression by affection status in 514 cases and 690 controls (PMID: 30115913). Various classes of classes were enriched in the differentially expressed genes, especially brain expressed genes and genes related to immune processes.

Study phs001932

Rapid Acceleration of Diagnostics - Digital Health Technologies (RADx-DHT): Digital Health Solutions for COVID-19: COVID Community Action and Research Engagement (COVID-CARE)

Vibrent Health will expand the Vibrent Digital Health Solutions Platform (DHSP) implementation to additional populations among diverse user groups for additional validation of the technology's performance, usability, and reliability in refinement of analytics generating predictive algorithms for infection and that support individual, organizational, community and societal-level decision-making in the COVID-19 pandemic response. This includes the aims to innovate a technology that can differentiate between COVID-19 and flu (or other respiratory illness); develop and test a novel WIFI-based contact tracing tool using a University’s enterprise WIFI system and software release of augmented contact tracing capabilities in Vibrent's DHSP; and develop a full technical integration approach and strategy to support data exchange between this solution and the NCI data hub.DOI: https://rapids.ll.mit.edu/10.57895/ravs-1b57

Study phs002533

Comparative Sequence Analysis Between Primary and Metastatic Colorectal Cancer Lesions

Molecular profiling for somatic mutations that predict response to anti-EGFR therapy in colorectal cancer (CRC) has become standard practice. However, abundant tissue from metastatic lesions is not always available from patients with metastatic CRC. Concerns involving genetic heterogeneity between primary and metastatic lesions have called into question the suitability of profiling primary tumors in patients with metastatic disease. Further, the identification of discordant mutations between matched primary and metastatic tumors would be of biological interest for the delineation of biomarkers of tumor progression and metastasis. To explore the degree of genetic heterogeneity between matched primary and metastatic tumors in CRC, we performed whole genome sequencing of four patient "trios" comprised of a primary colon tumor, a liver metastasis, and matched normal (non-cancerous) tissue. Somatic mutations and indels were called in each tumor and compared between primary and metastatic lesions.

Study phs000790

Structural Alterations Driving Castration-Resistant Prostate Cancer Revealed by Linked-Read Genome Sequencing

Adapted from manuscript in review: Nearly all prostate cancer deaths are from metastatic castration-resistant prostate cancer (mCRPC) but there have been few whole genome sequencing (WGS) studies of this disease state. We performed linked-read WGS on 23 mCRPC biopsy specimens and analyzed cell-free DNA sequencing data from 86 patients with mCRPC. In addition to frequent rearrangements affecting known prostate cancer genes, we observed complex rearrangements of the AR locus in most cases. These include highly recurrent tandem duplications involving an upstream enhancer of AR. A subset of cases also displayed a genome-wide tandem duplicator phenotype associated with CDK12 inactivation. Our findings highlight the complex genomic structure of mCRPC nominate new alterations that may inform prostate cancer treatment, and suggest that additional recurrent events in the noncoding mCRPC genome remain to be discovered.

Study phs001577

Single-cell analysis reveals different age-related somatic mutation profiles between stem and differentiated cells in human liver

Highly metabolic liver is exposed to many sources of spontaneous mutagenesis resulting in increased genome instability that, potentially, causes age-related functional liver failure. Here we comparatively characterize the somatic mutational landscape in single human liver cells from individuals of various ages. Mutation frequency is very high in normal human hepatocytes, increasing dramatically with age as compared to other tissues and cell types, e.g., B-cells, neurons, and clonal surrogates of various adult stem cells. Moreover, differentiated hepatocytes tend to accumulate more mutations compared to age-matched proliferating liver stem cells (LSCs). Mutation spectra also differ dramatically between different cell types. Elevated oxidative hallmarks are observed in mouse liver and ex vivo cultured LSCs, but not during liver aging. Overall, human liver is prone to high age-dependent genome instability, compared to other tissues, and reveals functional difference between LSCs and hepatocytes.

Study phs001956

CRISPR-Mediated ASD Gene Knockout Reduces Neuronal Activity

Autism Spectrum Disorder is phenotypically and genetically heterogeneous. We present a CRISPR gene editing strategy to insert a protein tag and premature termination sites creating an induced pluripotent stem cell (iPSC) knockout resource for functional studies of 10 ASD-relevant genes (AFF2/FMR2, ANOS1, ASTN2, ATRX, CACNA1C, CHD8, DLGAP2, KCNQ2, SCN2A, TENM1). Neurogenin 2 (NGN2)-directed induction of iPSCs allowed production of excitatory neurons, and mutant proteins were not detectable. RNAseq revealed convergence of several neuronal networks. Using both patch-clamp and multi-electrode array approaches, the electrophysiological deficits measured were distinct for different mutations. However, they culminated in a consistent reduction in synaptic activity, including reduced spontaneous excitatory post-synaptic current frequencies in AFF2/FMR2-, ASTN2-, ATRX-, KCNQ2- and SCN2A-null neurons. Despite ASD susceptibility genes belonging to different gene ontologies, isogenic stem cell resources can reveal common functional phenotypes, such as reduced functional connectivity.

Study phs001816

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