Search Results - EGA European Genome-Phenome Archive

Somatic Mutations and Their Etiological Determinants for Breast Cancer in African American Women (B-CAUSE Study)

The breast cancer health disparity between women of African ancestry (AA) and European ancestry (EA) remains a major public health challenge in the United States. AA women are afflicted by higher rate of triple-negative breast cancer (TNBC) and bear the highest mortality rate of all populations from the disease. Even within TNBC, some data suggest that AA women have poorer outcomes than EA women. Mounting evidence points to population differences in cancer biology, a fundamental question that remains unsettled. The disparity also manifests in representativeness in tumor sequencing projects, due to the low inclusion of AAs in genomic studies. A recent analysis of The Cancer Genome Atlas (TCGA) data revealed that the number of AA cases sequenced was sufficient only for studying frequently mutated genes (≥10%), and the power was worse for TNBC as a separate disease entity. As a result, the breast tumor mutational landscape elucidated to date is derived mostly from EA cases, and may not necessarily represent AA cancer genomes. Moreover, as discovery potential for new driver genes has come close to a plateau, cancer in AAs derived from distinct genetic and environmental contexts may provide a powerful venue for discovering mutations that are rare in EA cases. This is showcased in recent studies in colon and prostate cancer. Thus, we carried out a collaborative project, B-CAUSE, to characterize the mutational landscape of AA breast cancer genomes by pooling resources from five established studies, including the Women's Circle of Health Study (WCHS), the Black Women's Health Study (BWHS), the Southern Community Cohort Study (SCCS), the Nashville Breast Health Study (NBHS), and the Southern Tri-State Breast Health Study (STSBHS). This effort has created the largest AA-specific breast tumor mutation dataset to date in an efficient manner. The data deposited here are from the whole-exome sequencing (WES) of matched tumor-normal pairs of 462 TNBC in AA women from the B-CAUSE Study.

Study phs003962

Perceptions, Prevalence, and Patterns of Cannabis Use among Cancer Patients in NCI-Designated Cancer Centers

This study aimed to better understand the evolving landscape of cannabis use among patients undergoing cancer treatment across diverse geographic regions. It sought to characterize patterns of use, patient perceptions, and contextual influences such as legal status and provider engagement that affect cannabis use. Given the shifting legal environment, this study addresses a critical gap in the literature by providing data on how cancer patients integrate cannabis into their care. The available delivery methods of cannabis have also undergone dramatic changes and now include edibles, oils, tinctures, topicals, and inhaled forms. State-based policy changes are rapidly changing. Yet research on cannabis use by cancer patients across a variety of geographic settings remains limited. The extent of cannabis use, the perceived and real benefits and risks of use, potential interactions with cancer treatment and other medications, and impact on comorbid conditions are uncertain. Clinicians should be aware of the extent of use in order to assess potential drug-drug interactions, side effects, and contraindications; hence, an understanding of how cancer patients and clinicians engage in discussions about cannabis use is essential. Twelve NCI-designated cancer centers were awarded supplemental funding to conduct surveys assessing cannabis use among recently diagnosed cancer patients. Selected sites were in 8 states with varied legal status for medical and recreational cannabis use at the time of the survey. The 12 cancer centers independently received approval from their institutional review boards (IRB) and collected data from September 2021 to August 2023. Eligible participants were cancer patients or survivors who resided in their respective cancer center's catchment area. Cancer centers were responsible for sampling patients within their catchment area with the goal of 1,000 completed surveys. Ten out of 12 cancer centers drew probability samples of patients from patient lists defining their catchment area with some stratifying the sample in various ways including by cancer type, by sex, by race/ethnicity or by a combination of demographic variables.

Study phs004046

Kids First: Genetics of Pediatric Germ Cell Tumors

The Gabriella Miller Kids First Pediatric Research Program (Kids First) is a trans-NIH effort initiated in response to the 2014 Gabriella Miller Kids First Research Act and supported by the NIH Common Fund. This program focuses on gene discovery in pediatric cancers and structural birth defects and the development of the Gabriella Miller Kids First Pediatric Data Resource (Kids First Data Resource). All of the genomic and phenotypic data from this study are accessible through dbGaP. The data is also available at the Kids First Portal, where other Kids First datasets can also be accessed in the cloud for data analysis, data visualization, collaboration and interoperability, open to all researchers and developers.Pediatric malignant germ cell tumors (GCTs) represent approximately 6% of childhood cancers, including 3% of tumors in children aged 0-14 years and 15% of tumors in adolescents. GCTs are heterogeneous and grouped together due to the presumed common cell of origin, the primordial germ cell (PGC). GCTs typically occur in the testes or ovaries; however, extragonadal GCTs can occur and are likely a result of abnormal germ cell migration during development. Evidence suggests that GCTs, including those diagnosed in adults, are initiated in utero. Thus, alterations in normal embryonic development are likely to be especially relevant to GCT etiology. Germline susceptibility has not been evaluated in an agnostic fashion in pediatric GCT, mainly due to a lack of an adequate number of samples; however, emerging evidence supports a genetic etiology.In the two Kids First GCT projects, we will evaluate genetic susceptibility to intracranial and extracranial GCT by sequencing probands and their unaffected parents. The goals of the project are to: 1) evaluate the contribution of rare genetic variants in GCT through the use of aggregate burden tests, focusing on genes and established regulatory regions; 2) identify de novo SNVs and CNVs in pediatric GCT using a case-parent triad design; and 3) identify molecular signatures in GCT tumor specimens, overall and by age group and tumor characteristics. Whole Genome Sequencing (WGS) data generated through the Gabriella Miller Kids First Pediatric Research Program will provide an opportunity to investigate the genetic origins of GCT in a diverse set of samples. Given the limited knowledge of GCT etiology and biology, the results of the proposed analyses are likely to have a big impact on the field.

Study phs002322

Genomic Sequencing of Ewing Sarcoma

Pediatric Ewing sarcoma is a pediatric cancer that primarily arises from the bone. It is characterized by chimeric fusions of the EWS gene and an ETS family transcription factor. In this study, we performed massively parallel sequencing of a larger collection of Ewing sarcoma tumors to define the genomic landscape of this disease. We found that these tumors are among of the most genetically normal cancers currently characterized. There was also a marked absence of recurrent mutations in immediately targetable signaling transduction pathway genes. In this study we answer outstanding questions about ETS transcription factor expression, effects of treatment on mutational burden in Ewing sarcoma tumors, and describe patterns of tumor evolution. We also found that loss-of-function mutations in STAG2 were present in approximately 15% of Ewing sarcoma tumors and loss of STAG2 expression was associated with disease metastasis in this patient cohort.

Study phs000804

OICR-DAC, Ontario Institute for Cancer Research; Biliary Tract Cancer

Next Gen Sequencing data from Biliary Tract Cancers

Dac EGAC50000000528

Elucidating the molecular landscape of KRAS/BRAF mutant colorectal cancers

Study EGAS00001007459

Brain Cancer Center Committee

Dac EGAC00001003523

Proteogenomic Characterization Unveils Biomarkers Associated With Chemoresistance in Muscle Invasive Bladder Cancer

Cisplatin-based neoadjuvant chemotherapy (NAC) combined with radical cystectomy has been used as a standard of care for patients with clinically non-metastatic muscle invasive urothelial bladder cancer, but 40-50% patients will benefit from the treatment. Molecular subtypes of muscle invasive bladder cancer (MIBC) provide a possible biomarker roadmap that may help identify patients who may or may not respond to NAC. Recently, by integrating Mass Spectrometry-based proteomics, proteogenomic studies from the Clinical Proteomic Tumor Analysis Consortium (CPTAC) have demonstrated the potential of this approach in prioritizing candidate driver genes and facilitating understanding of the chemotherapy resistance mechanisms. To demonstrate the proteogenomic workflow for investigating the mechanisms underlying chemotherapy resistance in MIBC, we conducted proteogenomic characterization of 46 pre- and 14 post- treatment tumors, including whole exome sequencing (WES), mRNA sequencing, Tandem Mass Tag (TMT)-proteomics, or TMT-phosphoproteomic. These samples were selected from an initial cohort of 143 MIBC tissues and filtered by tumor purity, clinical history, pathological response, and proteomic quality control metrics. The final cohort comprised samples from 53 patients, including 45 with both genomic and proteomic data and 8 with genomic data only.Our multi-omics-based clustering reveals subtypes associated with chemotherapy sensitivity. Protein abundance of a short isoform of ATAD1 and RAF family proteins were identified as biomarkers of chemosensitivity which highlights the importance of proteomics data. Integration of proteomic and phosphoproteomic data reveals Wnt signaling via GSK3B-S9 phosphorylation and the JAK/STAT pathway as potential targets to overcome chemoresistance. Correlations between PD-L1 and TROP-2/NECTIN-4 indicate an additive benefit of combination therapy targeting these proteins. Our data analysis clearly demonstrates that proteogenomic plays an important role in uncovering potential resistance mechanisms that operate only at protein and Post-Translational Modification (PTM) levels. Proteomics data can be accessed through PRIDE with ID PXD060290. RNA-seq and whole-exome sequencing (WES) FASTQ files are archived in the dbGaP database.

Study phs004049

CSER: Evaluating Utility and Improving Implementation of Genomic Sequencing for Pediatric Cancer Patients in the Diverse Population and Healthcare Settings of Texas: The KidsCanSeq Study

Through this Clinical Sequencing Evidence-Generating Research (CSER) with Enhanced Diversity project we are completing a clinical study (The Texas KidsCanSeq Study) comparing the results of targeted cancer panel sequencing versus genome-scale testing in pediatric cancer patients across diverse clinical settings. We will compare the targeted pediatric cancer panel to germline whole exome sequencing (WES) of unselected childhood cancer patients. We will also compare an RNA/DNA targeted pediatric cancer panel versus WES, transcriptome sequencing and copy number array of FFPE tumor samples for the subset of patients with high-risk tumors. Exome sequencing is performed from a blood or saliva sample of the pediatric age (0-18) patient. We are building on our success completing the CSER program BASIC3 exome sequencing trial (which included 60% Hispanic and African-American patients from a single large academic center) in this large multi-institutional study of an even more diverse patient population from six pediatric oncology healthcare settings across Texas. Data from the Texas KidsCanSeq study will be submitted through the CSER Data Coordinating Center for access in NIH-supported databases.

Study phs002378

Childhood Cancer Data Initiative (CCDI): NCI-COG Pediatric MATCH Precision Medicine Clinical Trial

The National Cancer Institute-Children's Oncology Group (NCI-COG) Pediatric Molecular Analysis for Therapy Choice (MATCH) trial provides a framework for biomarker-driven early phase trials of targeted therapies in pediatric and young adult cancer patients across the United States. Pediatric MATCH enrolled more than 1,300 patients with treatment-refractory cancers, offering access to molecular screening and investigational targeted therapies. To further advance this, matched diagnostic, refractory tumor, and normal samples from Pediatric MATCH cases were molecularly characterized, creating one of the largest comprehensive data sets available for childhood cancers. This analysis has the potential to provide novel insights into the genetics of refractory pediatric, adolescent, and young adult cancers, as well as inform potential therapeutic strategies. The following molecular characterization assays were performed: Tumor whole exome sequencing (WES) Tumor whole genome sequencing (WGS) Tumor RNA sequencing (RNA-seq) Blood whole exome sequencing (WES) Blood whole genome sequencing (WGS)

Study phs002883

Epigenomics of Neurocognitive Function in Breast Cancer

This study harnessed the data and biospecimens from the Exercise Program in Cancer and Cognition (EPICC) study (parent study) that collected data on cognitive function, demographics, other symptoms and biospecimens at two time points (T1: enrollment, T2: six months later) within the context of a six-month randomized controlled trial of a moderate intensity aerobic exercise intervention. This study collected genome wide DNA methylation data from T1 and T2 and conducted epigenome-wide association-based analyses to find genes and biological pathways explaining variability in cognitive function and explaining how exercise mitigates cognitive decline. Our initial findings identified cg10331779 near CTNND2 (p-value=9.65×10-9) associated with processing speed and cg25906741 in MLIP (p-value=2.01×10-8) associated with subjectively measured cognitive function. Additionally, differentially methylated regions were identified near SLC6A11, PRKG1/CSTF2T, and FAM3B for processing speed and near PI4KB and SGCE/PEG10 for mental flexibility.

Study phs003959

Identifying and Reducing Disparities in Patient-Reported Outcomes Among African American Prostate Cancer Survivors

This research study aimed to identify disparities in prostate cancer symptom burden and their contributors among African American, Hispanic, and non-Hispanic White prostate cancer survivors. We collected patient-reported outcomes data, focusing on various aspects of the survivors' health and well-being, clinical data, demographics data, and germline genomic data.

Study phs003745

Parallel Genomic Alterations of Antigen and Payload Targets Mediate Polyclonal Acquired Clinical Resistance to the Antibody Drug Conjugate Sacituzumab Govitecan

Sacituzumab Govitecan (SG), a novel antibody drug conjugate (ADC) incorporating the anti-TROP2 antibody hRS7 conjugated to a topoisomerase-1 inhibitor (SN-38) payload, is the first ADC to be approved for advanced triple negative breast cancer (TNBC). However, mechanisms governing therapeutic resistance to SG are not known. We sought to identify mechanisms of de novo and acquired resistance to SG through unbiased whole-exome sequencing (WES) and RNA sequencing analysis of pre-treatment and multi-site post-progression (autopsy) tumor specimens. We examined three metastatic TNBC cases exhibiting (1) de novo progression, (2) stable disease, and (3) a deep response followed by progression, then mapped the temporal and spatial genomic evolution of acquired resistance in the responding patient. We then conducted additional pre-clinical experiments to validate the observed resistance mechanisms. TROP2 RNA and gene copy number were associated with de novo resistance, as case (1) was found to have absent TROP2 expression in all specimens, case (2) expressed TROP2, while case (3) exhibited both expression and focal genomic amplification of the TACSTD2/TROP2 locus. The genomic phylogeny tree inferred from case (3) post-progression specimens revealed one branch harboring an acquired canonical E418K resistance mutation in TOP1 (encoding topoisomerase 1) and a subsequent sub-clonal TOP1 inactivating frameshift mutation, while a distinct branch exhibited acquisition of a novel T256R missense mutation in TACSTD2 (encoding TROP2). Both the TOP1- and TACSTD2-mutant clones seeded multiple distinct metastatic sites. Through reconstitution experiments in TROP2 negative cells we found that TROP2 T256R is a stable protein with defective cell membrane localization and reduced cell surface binding by RS7 compared to wild-type TROP2. Collectively, these findings underscore TROP2 as a determinant of initial response to SG, and they reveal parallel and mutually exclusive polyclonal molecular mechanisms of acquired resistance involving the direct antibody target and drug payload target in distinct metastatic subclones of a single patient. While further research is needed to extend these novel findings, this study highlights the specificity of SG and illustrates how identifying such mechanisms will inform rational therapeutic strategies to overcome ADC resistance.  

Study phs002555

A Phase II Study: CRS207/GVAX Plus Anti-PD1 and Anti-CTLA4 Recruits Mesothelin- and KRAS-Specific T cells into PDAC

This study examined immunologic correlatives from a phase II study evaluating CRS207/GVAX vaccines in combination with anti-PD1 and anti-CTLA4 in metastatic pancreatic cancer (NCT03190265). Arm A received CRS207/GVAX with anti-PD1 and anti-CTLA4 therapy; Arm B received CRS207 with anti-PD1 and anti-CTLA4 therapy. Patients undergoing treatment in this trial had peripheral blood mononuclear cells (PBMCs) and tumor tissue biopsied serially at pre-treatment and on-treatment timepoints. Single-cell RNA/TCR sequencing was employed on PBMCs. Bulk RNA/TCR sequencing was employed on tumor tissues. We identified treatment-enriched inflammatory pathways as well as T cell repertoires.

Study phs003798

Whole Genome Sequencing for Metastatic Mutational Burden in Extraskeletal Myxoid Chondrosarcoma

Extraskeletal myxoid chondrosarcoma (EMC) is an ultra-rare cancer. Though it has a favorable prognosis and an indolent course, it has high rates of local recurrence and metastasis to the lungs. EMC is most often characterized by a translocation involving the NR4A3 gene most often fusing with EWSR1, leading to constitutive expression of NR4A3, the biological significance of which is unknown. Our study presents a case of EMC with case-matched lung and advanced pelvic metastases. We conducted Whole Genome Sequencing to examine differences in the mutational landscape at two different stages of metastasis. This is the first study to our knowledge to analyze mega-base scale structural variants (SVs) in EMC. Our data validates copy number variants (CNVs) found in previous studies. While the primary tumor and lung metastasis had similar somatic variations and CNVs, the pelvic metastasis had more SVs with especially increased mutational burden of SVs in chromosome 2. This suggests that different molecular drivers appear in more advanced, relapsing EMC compared with the primary tumor and early lung metastasis. The sequencing data is available through dbGaP.

Study phs003305

CSER: Exome Sequencing in Diverse Populations in Colorado and Oregon/CHARM Cancer Health Assessments Reaching Many

The CHARM (Cancer Health Assessment Reaching Many) study, part of the Clinical Sequencing Evidence-Generating Research (CS.ER2) effort, aimed to assess the utility of clinical exome sequencing and how it affects care in diverse populations. The study population included adults at risk for hereditary cancer syndromes. The primary objective was the implementation of a hereditary cancer risk assessment program in healthy 18-49 year-olds in primary care settings within a vertically integrated health delivery system (Kaiser Permanente) and a federal qualified health center (Denver Health). The investigators aimed to assess clinical exome sequencing implementation and interpretation, as well as tailored interactions for low health literacy including a contextualized consent process, and a modified approach to results disclosure and genetic counseling. The investigators were also assessing the clinical utility (healthcare utilization and adherence to recommended care) and personal utility of primary and additional results from clinical exome sequencing, and evaluate the ethical and policy implications of considering personal utility of genomic information decisions for health care coverage.Sequencing and analysis for CHARM was conducted at the Northwest Clinical Genomics Laboratory, University of Washington, Seattle (https://nwgc.gs.washington.edu/).

Study phs002111

Genomic and Immune Profiling of Breast Cancer Brain Metastases

Previous work has shown that breast cancer brain metastases (BCBrM) can have unique molecular profiles compared to extracranial tumors (ECTs), resulting in some patients demonstrating subtype switching between primary/extracranial tumors and brain metastases. Description of the biology of BCBrM and associations between biological features and clinical outcomes, particularly between molecular intrinsic subtypes, will facilitate the design of rational therapies for patients with BCBrM. To better characterize the molecular profiles of BCBrM, we conducted whole exome sequencing (WES) and total RNA sequencing (RNA-Seq) on BCBrM tissues, regardless of clinical or molecular subtype, obtained from a cohort of 42 patients from Duke University Medical Center. This cohort adds valuable patient samples to the field and enables strengthened investigation of somatic mutations, copy number alterations, gene expression profiles, and immune populations within and between BCBrM patients and other similar cohorts. The Duke BCBrM cohort includes clinical and molecular annotation of the 42 patient specimens and their associated WES and RNA-Seq data. Clinical and molecular (PAM50) intrinsic subtypes in ECTs and brain metastases were largely concordant within patients. There were observed differences in intrinsic subtype calls between frozen and FFPE specimens of the same tissue, with discordance mostly observed with LumB calls. Copy number alterations in chromosomal regions included clinically relevant genes, and somatic alterations were largely conserved within patients across matched samples, with few genes, including TP53, being recurrently altered in the majority of patient specimens. In matched FFPE brain metastasis and ECT samples, we observed differentially expressed genes and pathways that had increased or decreased expression in brain metastasis, including in oxidative phosphorylation and DNA repair. Survival outcomes for patients differed by intrinsic molecular subtypes, with some association between expression of select gene pathways and survival. Data available through dbGaP will be the sequencing data and sample attributes from BCBrM tissues obtained from 42 patients from Duke University Medical Center.

Study phs003673

MSK SPECTRUM - SPatiotemporal Evolution of Cancer Traced Using Multimodalities

MSK SPECTRUM is a multi-modal, interdisciplinary prospective study of spatiotemporal determinants of high-grade serous ovarian cancer (HGSOC) evolution, treatment and response. Accounting for ~80% of ovarian cancers, HGSOC is the most lethal gynecological malignancy and is a cancer of major unmet clinical need. Challenges in disease management relate to several unresolved questions about disease biology and diagnostic modalities. Prospective longitudinal collection of tissues and blood from laparoscopic biopsies and debulking surgeries enable multi-modal molecular measurements. The program brings together formidable expertise at Memorial Sloan Kettering Cancer Center (MSKCC) across the disciplines of high-resolution genomics and computer science, radiology and radiomics, surgery, tissue banking and sample preparation, medical oncology, immuno-oncology and high-resolution tissue profiling to generate a comprehensive and integrative dataset that will allow us to address the following major aims: i) characterize malignant and immune diversity at diagnosis, ii) survey the co-evolution of malignant cells and the immune response, and iii) stratify patients on standard-of-care and investigational compounds based on their genomic and transcriptomic signatures and changes to relevant genes (TP53, CCNE1, BRCA1/2, CDK12). The goal is to create a framework to utilize integrated multi-modal data as a route to advanced diagnostics and to ultimately establish a proof-of-concept for integrated diagnostics.

Study phs002857

WES in Angolan and Cape Verdean triple-negative breast cancer samples

WES in 23 Angolan and 7 Cape Verdean triple-negative breast cancer samples

Dac EGAC50000000486

High volume culture initiating in vitro evolution in neuroblastoma cell lines

Despite the advent of advanced molecular prognostic tools, it is still difficult to predict the course of disease for cancer patients at the individual level. This lack of predictability is also reflected in many experimental cancer model systems, begging the question of whether certain biological aspects of cancer (eg. growth, evolution etc.) can ever be anticipated or if there remains an inherent unpredictability to cancer, similar to other complex biological systems. We demonstrate by a combination of agent-based mathematical modelling, analysis of patient-derived xenograft systems from multiple cancer types, and in-vitro culture that certain conditions may invoke chaotic fluctuations in the clonal landscape of cancer growth. Our findings indicate that under those conditions, the cancer genome may behave as a complex dynamic system, making its long-term evolution inherently unpredictable.

Study EGAS00001007962

Genomic Characterization CS-MATCH-0007 Arm Q

The CS-MATCH-0007 protocol is part of a collaboration between the Center for Cancer Genomics (CCG) and the Division of Cancer Treatment and Diagnosis (DCTD) to perform whole-exome sequencing and RNA sequencing using pre-and post-treatment tumor biopsy specimens from patients enrolled on a treatment arm of the NCI-MATCH Clinical Trial (EAY131). The goal of this study is to identify the molecular basis for response and resistance to targeted therapies that are matched to specific genomic alterations found in their cancers. Arm Q is one of the treatment sub-protocols within the NCI-MATCH Clinical Trial (EAY131) where patients with HER2 amplification are treated with Kadcyla® (ado-trastuzumab emtansine). This subprotocol is one of the treatment arms included in the CS-MATCH-0007 protocol and will provide specimens for the program including tumor tissue and whole blood.

Study phs001926

International Cancer Proteogenome Consortium (ICPC): Proteogenomics of Early Stage Lung Adenocarcinoma in Taiwan

Lung cancer in East Asia is characterized by a high percentage of never-smokers with early-onset adenocarcinoma, predominantly with EGFR mutations. To provide an insight into the molecular phenotype of this demographically distinct disease, we have performed a proteogenomics study on a prospectively collected cohort representing early stage lung adenocarcinoma in Taiwan. The distinct mutational profile revealed a high prevalence of the APOBEC mutational signature in early-onset females, implicating differential regulation of APOBEC enzymes and DNA damage pathways, as well as enrichment of mutational signatures congruent with environmental carcinogens over-represented in the genomic location of EGFR. We delineate the proteogenomic hallmarks of tumor progression and propose a proteomics-informed classification that resolves the EGFR mutation heterogeneity associated with survival within the early stages. Functional annotation of the molecular subtypes by protein network analysis highlights candidate biomarkers for patient stratification. Our integrative analysis reveals the molecular architecture of lung cancer in East Asia and enables the path for precision medicine.

Study phs001954

Cancer Discovery Hub (CDH), National Cancer Center Singapore

This is a DAC for data deposited into EGA generated by Cancer Discover Hub, NCCS. The use of datasets in this portal is solely for research and academic use only, uses other than the have to be approved by the relevant DAC members.

Dac EGAC50000000039

Somatic Mutation in Normal Bladder Study

Adult human somatic tissues are landscapes of mutant clones, but little is known about how these landscapes are shaped by known cancer risk factors. The goal of this study was to determine how the main bladder cancer risk factors (sex and smoking) change the mutational landscape of the normal urothelium. We collected normal urothelium from 45 donors at autopsy by brushing ~2cm² of the surface epithelium in the upper part (dome) and lower part (trigone) of the bladder (79 samples total). To identify mutations with high sensitivity we employed ultradeep (~5000x) DNA error-correcting duplex-sequencing on a panel of 15 protein coding genes and the TERT promoter, previously described to be under positive selection in normal urothelium or relevant to bladder cancer. We identified thousands of clonal driver mutations, which demonstrate pervasive positive selection in the normal urothelium. Males showed a significantly higher number of driver truncating mutations in RBM10, CDKN1A and ARID1A, despite similar rates of non-coding mutations, indicating stronger positive selection and clonal expansion in the male urothelium. We also discovered clonal expansions driven by activating TERT promoter mutations in the normal bladder, which were strongly associated with age and smoking. These results demonstrate that sex and smoking shape the clonal landscape of the normal bladder and indicate that the high mutational content of normal tissues might be leveraged to study the effect of mutations in vivo (i.e. natural saturation mutagenesis). We will deposit in dbGaP de-identified relevant clinical information from the 45 donors and the fastq files derived from duplex sequencing of the 79 samples in the study. We will also deposit fastq files derived from duplex sequencing of 3 control cord blood samples.

Study phs004105

Epigenetic Control of Topoisomerase 1 by MacroH2A1.1

DNA transactions introduce torsional constraints that pose an inherent risk to genome integrity. While topoisomerase 1 (TOP1) activity is essential for removing DNA supercoiling, aberrant stabilization of TOP1:DNA cleavage complexes (TOP1ccs) can result in cytotoxic single-stranded DNA lesions (SSLs). What protects the genome from aberrant TOP1 activity remains unknown. Using a combination of CUT&RUN and TOP1 Covalent Adduct Detection (CAD) Seq in MDA-MB-231 breast cancer cells (American Type Culture Collection, ATCC), we identified chromatin context as an essential means to ensure TOP1cc resolution at TOP1 hot spots. Through its ability to bind poly(ADP-ribose) (PAR), a protein modification required for TOP1cc repair, the histone variant macroH2A1.1 establishes a TOP1-permissive chromatin environment, while the alternatively spliced macroH2A1.2 isoform is unable to bind PAR or protect from TOP1ccs. MacroH2A1 isoform-specific analyses were based on reconstitution of macroH2A1.1 knockout cells with wild-type or PAR binding-deficient FLAG-tagged macroH2A1.1 in human breast cancer cells. Mechanistically, we find that macroH2A1.1 facilitates the recruitment of the TOP1cc repair factor XRCC1 in response to both endogenous and drug-induced topological stress. Impaired macroH2A1.1 splicing, a frequent cancer feature, was predictive of increased sensitivity to TOP1 poisons in a pharmaco-genomic screen in breast cancer cells, and macroH2A1.1 inactivation mirrored this effect in breast and ovarian cancer cells. Consistent with this, low macroH2A1.1 expression correlated with improved survival in cancer patients treated with TOP1 inhibitors (TOP1i). We propose that macroH2A1 alternative splicing serves as an epigenetic modulator of TOP1-associated genome maintenance and a potential cancer vulnerability.

Study phs003729

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