Search Results - EGA European Genome-Phenome Archive

L1-Seq and Genome-Wide SNP Genotyping in a Multiethnic Asian Population

Insertions of the human-specific subfamily of LINE-1 (L1) retrotransposon are highly polymorphic across individuals and can critically influence the human transcriptome. We hypothesized that L1 insertions could represent genetic variants determining important human phenotypic traits, and performed an integrated analysis of L1 elements and single nucleotide polymorphisms (SNPs) in several human populations. We found that a large fraction of L1s were in high linkage disequilibrium (LD) with their surrounding genomic regions and that they were well-tagged by SNPs. However, L1 variants were only partially captured by SNPs on standard SNP arrays, so that their potential phenotypic impact would be frequently missed by SNP array-based genome-wide association studies. We next identified potential phenotypic effects of L1s by looking for signatures of natural selection linked to L1 insertions; significant extended haplotype homozygosity (EHH) was detected around several L1 insertions. This suggests that some of these L1 insertions may have been the target of recent positive selection.

Study phs000732

A Phase III Randomized Study of Nivolumab Plus Ipilimumab Versus Nivolumab in Stage IV Squamous Cell Lung Cancer

Lung-MAP (S1400, NCT02785952) was a multicenter, open-label, phase III randomized clinical trial. The Lung-MAP-I substudy (S1400I) was conducted from December 2015 to April 2018, through the National Clinical Trials Network and led by the SWOG Cancer Research Network. The trial compared nivolumab plus ipilimumab (nivo+ipi) with nivolumab monotherapy (nivo) in patients with chemotherapy-pretreated, immunotherapy-naïve, advanced squamous non-small cell lung carcinoma (sqNSCLC). Two hundred fifty-two patients were randomly assigned to receive nivo+ipi (n = 125) or nivo (n = 127). The clinical efficacy endpoints were overall survival, progression free survival, duration of response, and best objective response by RECIST 1.1. Multi-omic translational analysis was performed in collaboration with the the CIMAC–Cancer Immunologic Data Commons (CIDC) Network using available tumor tissue samples and blood samples (n = 160) submitted for Lung-MAP screening and provided by the SWOG tissue bank.

Study phs003412

Genetic Analysis of Latin American Cervical Cancer

HPV16 is the most oncogenic type of human papillomaviruses (HPV). Integration of HPV into the human genome is an important mechanism of carcinogenesis but is absent in at least 30% of HPV16+ tumors. We applied long-read whole-genome sequencing (WGS) to cervical cancer cell lines and tumors to characterize HPV16 carcinogenesis in the absence of integration. WGS of HPV16+ cervical tumor samples from Latin America revealed that 11/20 tumors with only episomal HPV (EP) had intact monomer episomes. The remaining 9 EP tumors had multimer and rearranged HPV genomes. The majority (80%) of the HPV rearrangements and deletions disrupted the E1 and E2 genes, and EP tumors overexpressed the E6 and E7 viral oncogenes, a similar profile to tumors with HPV integration. Tumors with putative multimer HPV integrations display HPV multimers and concatemers of human and viral sequences. Our data uncovered a novel mechanism for HPV16 to cause cancer without integration through aberrant episomal replication, and forming rearranged, mutated, and multimer episomes.

Study phs002810

Multi-Ethnic Study of Atherosclerosis (BioLINCC)

The Multi-Ethnic Study of Atherosclerosis (MESA) is a study of the characteristics of subclinical cardiovascular disease (disease detected non-invasively before it has produced clinical signs and symptoms) and the risk factors that predict progression to clinically overt cardiovascular disease or progression of the subclinical disease. MESA researchers study a diverse, population-based sample of 6,814 asymptomatic men and women aged 45-84. Thirty-eight percent of the recruited participants are white, 28 percent African-American, 22 percent Hispanic, and 12 percent Asian, predominantly of Chinese descent. Data available for request include phenotypic data previously released on BioLINCC as well as raw images (E.g. Echocardiogram) and raw tracing data files (e.g. Electrocardiogram). These new data are intended to be made available to interested researchers via BioData Catalyst, will include participants irrespective of participation in genetics (i.e. the full MESA cohort), and may be merged with currently posted (to dbGaP) phenotype and molecular datasets (WGS, GWA, RNA Seq, Methylation, Metabolomics, and Proteomics).

Study phs003288

Integrative Somatic and Germline Computational Biology to Redefine Clinical Actionability in Solid Tumors

Neuroendocrine tumors (NETs) are rare cancers that arise in the gastrointestinal tract and pancreas. The fundamental mechanisms driving gastroenteropancreatic NETs (GEP-NETs) growth remain incompletely elucidated; however, the heterogeneous clinical behavior of GEP-NETs suggests that both cellular lineage dynamics and tumor microenvironment influence tumor pathophysiology. Here, we performed single-cell RNA-sequencing (scRNA-seq) of fresh resections of GEP-NETs, including four pancreatic NETs, three small intestinal NETs, and one perigastric NET. We used single-cell sequencing to investigate the tumor and immune cellular landscapes of GEP-NET patients. Malignant GEP-NET gene and regulon expression was compared with normal, gastrointestinal endocrine cell differentiation and fate determination stages. We further characterized immune-immune and immune-tumor interaction networks within GEP-NETs, identifying novel therapeutic opportunities in the myeloid compartment of the microenvironment. Our findings highlight the transcriptomic heterogeneity that distinguishes the cellular landscapes of GEP-NET anatomic subtypes and reveal potential avenues for future precision medicine therapeutics.

Study phs003141

BarcUVa-Seq (Biology of Colorectal Cancer Risk Enhancers)

This study was designed to generate a cohort of normal colon mucosal biopsies from the "average risk" population. Its primary aims included the development of an RNA-seq dataset of normal colon mucosal biopsies across three colon regions (ascending, transverse and descending). Further, we aimed to provide plausible prioritization to genetic components of colorectal cancer risk by employing methods such as expression quantitative trait loci analysis. In doing so, we provide a novel reference dataset for the study of colon cancer risk in the healthy colon epithelium. RNA-seq was performed in batches on an Illumina HiSeq 2500 (batch 1-7) or NovaSeq 6000 (batch 8) on a total of 463 samples. Matched genotyping data was generated on the Illumina OncoArray BeadChip. Phasing was carried out using Minimac 3 and imputation was performed using The Haplotype Reference Consortium panel on the Michigan Imputation Server.Genotype and RNA-seq data will be made available in dbGaP.

Study phs003338

Deterministic Evolution and Stringent Selection During Pre-Neoplasia

The earliest events during human tumor initiation are poorly characterized but may hold clues as to how to detect and prevent malignancy. Here we model this occult process by engineering TP53 deficiency in primary human gastric organoids and performing experimental evolution in multiple clonally derived cultures over two years, thereby defining causal relationships between this common initiating genetic lesion and resulting phenotypes. TP53 loss induced progressive aneuploidy, including copy number alterations and complex structural variants that are common in established gastric cancers, and which accrued along a defined temporal order. Longitudinal single cell sequencing of TP53 deficient gastric organoids similarly indicates progression towards malignant transcriptional programs. Moreover, lineage tracing with expressed cellular barcodes revealed highly reproducible dynamics whereby initially rare subclones with shared transcriptional programs repeatedly attain clonal dominance. This powerful platform for experimental evolution reveals stringent selection and convergence at the genotypic and phenotypic levels in pre-malignant epithelial organoids, illuminating evolutionary constraints and barriers to malignant transformation.

Study phs003249

Unraveling the Genetic Architecture of Diabetic Retinopathy in South India

This study aims to understand the genetic architecture of diabetic retinopathy in the South Indian population by examining participants with South Indian ancestry and type 2 diabetes (T2D) from two sources: the Sankara Nethralaya-Diabetic Retinopathy Epidemiology and Molecular Genetic Study (SN-DREAMS) and prospective recruitment at Sankara Nethralaya affiliates. A total of 2393 patients were recruited and included in the genetic analysis, with 1588 patients having no diabetic retinopathy (DR) serving as the controls and 805 patients with any level of DR serving as the cases. Enrolled individuals had genome-wide genotyping from DNA extracted from blood samples. In addition, whole genome sequencing (WGS) was performed on 31 members from 2 families. Clinical data, such as age, duration of diabetes, and hemoglobin A1C (HbA1c) were recorded for study participants. Diabetic retinopathy was assessed by clinical exam and/or fundus photography. The grading of diabetic retinopathy followed the International Clinical Diabetic Retinopathy Severity Scale.

Study phs002116

Structure of the Mucosal and Stool Microbiome in Lynch Syndrome

The gut microbiota has been associated with colorectal cancer (CRC), but causal alterations preceding CRC have not been elucidated. To prospectively assess microbiome changes prior to colorectal neoplasia, we investigated samples from 100 Lynch syndrome patients using 16S rRNA gene sequencing of colon biopsies, coupled with metagenomic and metatranscriptomic sequencing of feces. Colectomy and CRC history represented the largest effects on microbiome profiles. A subset of Clostridiaceae were depleted in stool corresponding with baseline adenomas, while Desulfovibrio was enriched in both stool and mucosal biopsies. A classifier leveraging stool metatranscriptomes resulted in modest power to predict interval development of preneoplastic colonic adenoma. Predictive transcripts corresponded with a shift in flagellin contributors and oxidative metabolic microenvironment, potentially factors in local CRC pathogenesis. This suggests that the effectiveness of prospective microbiome monitoring for adenomas may be limited but supports the potential causality of these consistent, early microbial changes in colonic neoplasia.

Study phs002343

Identification of High-Risk PHF19 Expressing Cells in Myeloma Single-Cell Multiomics

The aim of this study is to identify novel subsets of cells that are associated with progression and response to treatment. In this project, we study the tumor fraction from 49 myeloma patients across stages of progression. Samples were collected from 10 smoldering multiple myeloma (SMM), 22 newly diagnosed multiple myeloma (NDMM), and 17 relapsed refractory multiple myeloma (RRMM) patients. These samples were then sorted using magnetic-activated cell sorting (MACS) for CD138+ cells that represent the tumor fraction of each sample. The CD138+ fraction then underwent whole genome sequencing (WGS), where possible, and single-cell multiomics. Single-cell multiomics can now measure scRNA-seq and scATAC-seq simultaneously, which we use in this project. Using single-cell multiomics, we will study subclonal changes in gene expression, chromatin accessibility, and identify novel regulatory relationships within myeloma tumors. Furthermore, we will apply state of the art single-cell and single-cell multiomic techniques to better identify the more high-risk components of myeloma.

Study phs003220

Ipilimumab and Decitabine in Treating Patients With Relapsed or Refractory Myelodysplastic Syndrome or Acute Myeloid Leukemia

The NCI Experimental Therapeutics Clinical Trials Network (ETCTN)/Cancer Therapy Evaluation Program (CTEP) 10026 study (NCT02890329) tested combined ipilimumab and decitabine treatment in two cohorts: Arm A consisted of patients with relapsed acute myeloid leukemia (AML) after allogeneic hematopoietic stem cell transplantation. Arm B consisted of patients with advanced myelodysplastic syndrome (MDS) or AML that did not previously undergo stem cell transplantation. During the study, peripheral blood and bone marrow samples were obtained from study participants at study entry (screening), following the first lead-in cycle of decitabine monotherapy, during combined treatment with decitabine and ipilimumab, and at the end of treatment.This study tested the combination of the CTLA-4 blocking antibody ipilimumab and the DNA methyltransferase inhibitor decitabine in advanced myeloid disease in the transplant-naive and post-transplant context. The samples were used for bulk and single cell RNA sequencing (scRNA-seq) as well as whole exome sequencing (WES).

Study phs003015

Single cell chromatin accessibility allows analysis of the transposable element landscape, revealing shared features of immune tissue-residency

Tissue adaptation is required for regulatory T (Treg) cells to function within organs. Whether this program shares similarities between different tissue-localized immune populations is poorly understood. Here, we addressed this by analyzing single-cell chromatin accessibility data, including the transposable element (TE) landscape, of CD45+ immune cells from different tissues. We identified features of organ-specific tissue adaptation across different immune cells. Focusing on tissue-Treg cells, we found that the Treg tissue adaptation program was conserved in other tissue-localized immune cells, such as amphiregulin-producing Th17 cells. Accessible TEs can act as regulatory elements but their contribution to tissue adaptation is unclear. TE landscape analysis revealed an enrichment of specific transcription factor binding motifs in TE regions within accessible chromatin peaks. TEs, specifically from the LTR family, were located in enhancer regions and associated with tissue adaptation. These findings broaden our understanding of immune tissue-residency, an important step towards organ-specific immune interventions.

Study EGAS50000000350

MutWP6__CRUK_Grand_Challenge_Mutographs_of_Cancer__alkylating_agents

The Mutographs project aims to advance our understanding of the causes of cancer through studies of mutational signatures. Led by Mike Stratton, together with Paul Brennan, Ludmil Alexandrov, Allan Balmain, David Phillips and Peter Campbell, this large-scale international research endeavour was awarded a Cancer Research UK Grand Challenge. Within Mutographs, work lead by the Sanger Institute will investigate whether detection of somatic mutations and mutational signatures in circulating white blood cells can be developed into a practical, generic system for surveying and monitoring multiple different endogenous and exogenous exposures, providing an ‘observatory’ on somatic mutational processes in humans. Whole genome sequences are generated at the Wellcome Sanger Institute (Illumina HiSeqX). Somatic mutational signatures are subsequently extracted by non-negative matrix factorisation methods. Through an enhanced understanding of cancer aetiology, Mutographs unprecedented effort is anticipated to outline modifiable risk factors, lead to new approaches to prevent cancer, and provide opportunities to empower early detection, refine high-risk groups and contribute to further therapeutic development.

Study EGAS00001003637

MutWP6__CRUK_Grand_Challenge_Mutographs_of_Cancer__oncology_agents

he Mutographs project aims to advance our understanding of the causes of cancer through studies of mutational signatures. Led by Mike Stratton, together with Paul Brennan, Ludmil Alexandrov, Allan Balmain, David Phillips and Peter Campbell, this large-scale international research endeavour was awarded a Cancer Research UK Grand Challenge. Within Mutographs, work lead by the Sanger Institute will investigate whether detection of somatic mutations and mutational signatures in circulating white blood cells can be developed into a practical, generic system for surveying and monitoring multiple different endogenous and exogenous exposures, providing an ‘observatory’ on somatic mutational processes in humans. Whole genome sequences are generated at the Wellcome Sanger Institute (Illumina HiSeqX). Somatic mutational signatures are subsequently extracted by non-negative matrix factorisation methods. Through an enhanced understanding of cancer aetiology, Mutographs unprecedented effort is anticipated to outline modifiable risk factors, lead to new approaches to prevent cancer, and provide opportunities to empower early detection, refine high-risk groups and contribute to further therapeutic development.

Study EGAS00001004125

Single-cell RNA sequencing of human skin tumors (BCC, SCC and Melanoma)

Cancer-associated fibroblasts (CAFs) play a key role in cancer progression and treatment outcome. Here, we elucidate the yet unresolved intra-tumoral CAF variety in three skin cancer types at molecular and spatial single-cell resolution in a large cohort. We show that two out of three CAF subtypes contribute to tumor immune surveillance with distinct mechanisms. Matrix CAFs (mCAFs) ensheath tumor nests and synthesize extracellular-matrix to prevent T cell invasion. Immunomodulatory CAFs (iCAFs), which express proinflammatory and immunomodulatory factors, are only detected in high abundance in aggressive tumors. Strikingly, iCAFs but not tumor cells are (apart from immune cells) the exclusive cell type producing chemokines and, thus, play a key role in immune cell recruitment and activation. Mechanistically, we show that cancer cells transform adjacent healthy fibroblasts into cytokine-expressing iCAFs, which subsequently recruit immune cells and modulate the immune response. In conclusion, targeting CAF variants holds promise for improved efficacy of immunotherapy.

Study EGAS50000000365

Base-excision repair pathway shapes 5-methylcytosine deamination signatures in pan-cancer genomes

Transition of cytosine to thymine in CpG dinucleotides is the most frequent type of mutation in cancer. This increased mutability is commonly attributed to spontaneous deamination of 5-methylcytosine (5mC), which is normally repaired by the base-excision repair (BER) pathway. However, the contribution of 5mC deamination in the increasing diversity of cancer mutational signatures remains poorly explored. Here, we integrate mutational signatures analysis in a large series of tumor whole genomes with lineage-specific epigenomic data to draw a detailed view on 5mC deamination in cancer. We uncover tumor type-specific patterns of 5mC deamination signatures in CpG and non-CpG contexts. We demonstrate that the BER glycosylase MBD4 preferentially binds to open chromatin domains, which correlates with lower mutational burden in these domains. We validate our findings by modelling BER deficiencies in isogenic cell models. Overall, we establish MBD4 as the main actor responsible for 5mC deamination repair in humans.

Study EGAS50000000536

Integrative Molecular Characterization of Breast Cancer

Version 1: We have performed integrative analyses of breast cancer tumors, including whole exome sequencing (WES) of tumor and normal pairs, whole transcriptome sequencing, and single-cell RNA sequencing (scRNA-seq) or single-nucleus RNA sequencing (snRNA-seq), to determine molecular correlates of response to novel and immune therapies. We have focused on dissecting the role of anticancer immunity in response to these therapies and understanding biological mechanisms underlying therapeutic resistance. The goal of this work is to advance a precision medicine approach to breast cancer treatment by identifying molecular biomarkers to improve therapy selection and novel therapeutic targets to overcome resistance. Version 2: We performed bulk whole exome sequencing (WES) of fresh frozen tissue from primary hormone receptor-positive breast cancer. Additionally, where available, we performed bulk whole transcriptome sequencing for the same individuals (tumor only). Additionally, we performed single cell sequencing on fresh frozen tissue from primary hormone receptor-positive breast cancer.

Study phs002419

Plasma mutation profile of precursor lesions and colorectal cancer using the Oncomine Colon cfDNA Assay

Colorectal cancer (CRC) is the second leading cause of cancer death worldwide. Early detection of precursor lesions or early-stage cancer could hamper cancer development or improve survival rates. Liquid biopsy, which detects tumor biomarkers, such as mutations, in blood, is a promising avenue for cancer screening. To assess the presence of genetic variants in plasma cell-free tumor DNA from patients with precursor lesions and colorectal cancer using the commercial Oncomine Colon cfDNA Assay. Cell-free DNA (cfDNA) samples from the blood plasma of 52 Brazilian patients were analyzed. Eight patients did not have any significant lesions (five normal colonoscopies and three hyperplastic polyps), 24 exhibited precursor lesions (13 nonadvanced adenomas, ten advanced adenomas, and one sessile serrated lesion), and 20 patients with cancer (CRC). The mutation profile of 14 CRC-associated genes were determined by next-generation sequencing (NGS) using the Oncomine Colon cfDNA Assay in the Ion Torrent PGM/S5 sequencer.

Study EGAS50000000471

MP2PRT: Genomic and Molecular Characterization of Biomarkers Associated with Tumor Angiogenesis, DNA Repair, and Immunologic Tolerance using Samples from the NRG Oncology Phase 3 Randomized Trial, GOG-0240 (NCT00803062)

The Molecular Profiling to Predict Response to Treatment (MP2PRT) program is part of the NCI's Cancer Moonshot Initiative. The aim of this program is the retrospective characterization and analysis of biospecimens collected from completed NCI-sponsored trials of the National Clinical Trials Network and the NCI Community Oncology Research Program. This study is one of the selected studies under this program. For this study, genomic characterization (WGS, WXS, Total RNAseq, miRNAseq) has been performed on cervical tumor tissue from patients with advanced disease (persistent, recurrent, and metastatic) and matching germline samples. It is hypothesized that the characterization of these tissues using next generation sequencing will lead to the identification of relevant novel genetic aberrations within the immunologic, DNA repair, and tumor angiogenesis domains that dichotomize the study population into exceptional responders and non-responders to systemic therapy, with a spectrum of response manifesting between the two extremes.

Study phs002293

Oncogenic FOXL2C134W has gain-of-function chromatin remodeling activity that reprograms glucocorticoid receptor occupancy to promote ovarian granulosa cell tumor growth

Adult type ovarian granulosa cell tumors (AGCTs) are rare malignancies with near universal somatic mutation c.C402G (p.Cys134Trp) in FOXL2, a forkhead box-family transcription factor important for ovarian function. Relapsed AGCT is incurable and the mechanism of the unique FOXL2 mutation remains incompletely understood. To identify FOXL2C134W-dependent pharmacologic synergies, we created and characterized endogenous FOXL2 isogenic AGCT cells and an AGCT tumoroid biobank. A drug screen identified that glucocorticoids promote FOXL2C134W-dependent AGCT growth. Epigenetic investigation revealed that the Cys134Trp mutation exposes latent DNA sequence-specific pioneering activity in FOXL2, a unique oncogenic mechanism. FOXL2C134W pioneering activity redirects glucocorticoid receptor chromatin occupancy to drive hyaluronan synthase 2 gene expression and increase extracellular hyaluronan secretion. Treatment of AGCT models with hyaluronidase reduces viability and this effect can be rescued by dexamethasone. Thus, gain-of-function pioneering activity contributes to the oncogenic mechanism of FOXL2C134W and creates a potentially targetable synergy with glucocorticoid signaling.

Study EGAS50000000622

Single cell sequencing data of PBMC and CSF from a cohort of Multiple Sclerosis patients and other neurological disease controls

Neuroinflammation is often characterised by immune cell infiltrates in the cerebrospinal fluid (CSF). Here we apply single-cell RNA sequencing to explore the functional characteristics of these cells in patients with various inflammatory, infectious and non-inflammatory neurological disorders. We show that CSF is distinct from the peripheral blood in terms of both cellular composition and gene expression. We report that the cellular and transcriptional landscape of CSF is altered in neuroinflammation, but is strikingly similar across different neuroinflammatory disorders. We find clonal expansion of CSF B and T cells in all disorders but most pronounced in inflammatory diseases, and we functionally characterise the transcriptional features of these cells. Finally, we explore the genetic control of gene expression in CSF lymphocytes. Our results highlight the common features of immune cells in the CSF compartment across diverse neurological diseases and may help to identify new targets for drug development or repurposing in Multiple Sclerosis.

Study EGAS50000000739

Multi-Omic Investigation of Beckwith-Wiedemann Syndrome Hepatoblastoma

Hepatoblastoma (HB) is the most common malignant liver tumor diagnosed in children under 5 years of age. One of the most common HB predisposition syndromes is Beckwith-Wiedemann Syndrome (BWS, OMIM 130650), which affects approximately 1/10,000 live births. In this study, we perform Whole Exome Sequencing (WES), DNA methylation array, messenger RNA-Sequencing (mRNA-Seq), and microRNA-Sequencing (miRNA-Seq) to examine the genomic, methylomic, and transcriptomic signature of BWS HB. We analyzed five tumor-normal paired samples, two BWS tumor only samples, and five non-BWS control samples to identify a predisposition and oncogenic signature of BWS HB development. To further understand the new impact of 11p15 changes, specifically in the liver, we performed single-nucleus RNA sequencing (snRNA-seq) and single-nucleus assay for transposase-accessible chromatin with sequencing (snATAC-seq) to generate paired, cell-type-specific transcriptional and chromatin accessibility profiles of both BWS-liver and nonBWS-liver nontumorous and tumor tissues.

Study phs002614

MethylBERT enables read-level DNA methylation pattern identification and tumour deconvolution using a Transformer-based model

DNA methylation (DNAm) is a key epigenetic mark that shows profound alterations in cancer. Read-level methylomes enable more in-depth DNAm analysis due to the broad coverage and preservation of rare cell-type signals, compared to array-based data such as 450K/EPIC array. Here, we propose MethylBERT, a novel Transformer-based model for read-level methylation pattern classification. MethylBERT identifies tumour-derived sequence reads based on their methylation patterns and genomic sequence and the method estimates tumour cell fractions within bulk samples. In our evaluation, MethylBERT outperforms existing deconvolution methods and demonstrates high accuracy regardless of methylation pattern complexity, read length and read coverage. Moreover, we show its applicability to cell-type deconvolution as well as non-invasive early cancer diagnostics using liquid biopsy samples. MethylBERT represents a significant advancement in read-level methylome analysis and enables accurate tumour purity estimation. The broad applicability of MethylBERT will enhance studies on both tumour and non-cancerous bulk methylomes.

Study EGAS50000000806

Healthy and FPD Bone Marrow Single Cell Sequencing

Familial platelet disorder (FPD) is caused by germline RUNX1 mutations. Families inheriting the disease suffer from platelet dysfunction and consequently various bleeding disorders. The life long risk of developing leukemia increases in FPD individuals by 40% and the onset is at 29 years old. In order to understand the mechanism behind disease transformation, we performed single cell sequencing on mononuclear bone marrow cells from 10 FPD and 4 healthy control individuals. The participants were between 6 and 72 years of age at time of bone marrow collection and were not diagnosed with any leukemia. Following the established Ficoll paque assay, the mononuclear cells were used to perform 10x chromium single cell, the data was analyzed through Seruat packages, and further analysis was done to access differences between FPD and healthy. The most distinguished feature between FPD and healthy was the upregulation of inflammation and inflammatory related disease. These findings were further validated and used to design an inhibitory assay for reversal of FPD phenotype.

Study phs003508

Nivolumab plus chemotherapy or ipilimumab in gastroesophageal cancer: CheckMate 649 biomarker analyses

First-line nivolumab-plus-chemotherapy demonstrated superior overall survival (OS) versus chemotherapy for advanced gastroesophageal adenocarcinoma (CheckMate 649). Nivolumab-plus-ipilimumab provided durable responses and higher survival rates versus chemotherapy; however, the prespecified OS significance boundary was not met. To identify biomarkers predictive of differential efficacy outcomes, exploratory analyses were performed using whole-exome sequencing and RNA sequencing. Nivolumab-based therapies demonstrated improved efficacy versus chemotherapy in hypermutated and, to a lesser degree, Epstein Bar Virus-positive tumors compared with chromosomally unstable and genomically stable tumors. Within the KRAS-altered subgroup, only patients treated with nivolumab-plus-chemotherapy demonstrated improved OS benefit versus chemotherapy. Low stroma gene expression signature scores were associated with OS benefit with nivolumab-based regimens; high regulatory T-cell signatures were associated with OS benefit only with nivolumab-plus-ipilimumab. Our analyses suggest that distinct and overlapping pathways contribute to the efficacy of nivolumab-based regimens in gastroesophageal adenocarcinoma.

Study EGAS50000000747

Multi-Omic Microbiome Study-Pregnancy Initiative (MOMS-PI)

The Vaginal Microbiome Consortium team at Virginia Commonwealth University has conducted the Multi-Omic Microbiome Study: Pregnancy Initiative (MOMS-PI) in collaboration with the Global Alliance to Prevent Prematurity and Stillbirth (GAPPS) to better understand how microbiome and host profiles change throughout pregnancy and influence the establishment of the nascent microbiome in neonates. The team particularly focused on elucidation of the role of the microbiome and its components in the etiology of preterm birth, which occurs in over 10% of pregnancies and which is the leading cause of death in neonates. Samples from 1594 women and their neonates were collected throughout pregnancy, at delivery and postpartum. The group has generated a comprehensive dataset of multiple omics technologies. This longitudinal, large-scale effort was designed to provide a large-scale resource for the scientific community. The study also permits characterization of temporal dynamics of the microbiome in pregnancy and factors associated with preterm birth.

Study phs001523

Targeted Mutational Analysis of Intestinal T-cell Lymphomas, Using a Customized Targeted Amplicon Panel on the Ion Torrent PGM

Intestinal T-cell lymphomas (ITCL) are rare, aggressive T-cell lymphomas that are composed primarily of enteropathy-associated lymphomas Type 1 and type 2, and a small fraction of cases not classifiable as EATL that are classified as peripheral T-cell lymphoma, not otherwise classifiable. The molecular pathogenesis of these rare lymphomas is largely unknown. We studied a series of 34 ITCL cases using a combination of amplicon based targeted next generation sequencing and pyrosequencing for mutations in 34 genes previously reported to be mutated in other types of T-cell lymphomas and other genes known to have significant roles in normal T-cell proliferation. We identified a high percentage of cases with mutations in JAK/STAT signaling pathway members, and also in RAS family members. Notably, we did not detect GNAI-2 mutations in our North American cases of EATL type 2 by targeted pyrosequencing, which had been reported previously in Asian cases.

Study phs001126

Uncovering Gene Regulatory Differences between Human and Chimpanzee Neural Cells

A major challenge in human evolutionary biology is to pinpoint the genetic differences that underlie phenotypic changes in the human lineage, such as increased neuron number and a prolonged period of neuronal maturation. Here, we used human-chimpanzee tetraploid cells to distinguish changes in gene expression due to cis-acting sequence variants that change local gene regulation, from trans expression changes due to species differences in the cellular environment, in neural progenitor cells and excitatory neurons using RNA-seq and ATAC-seq. Using a CRISPR inhibition screen with scRNA-seq, transcription factor motif analyses with CUT&Tag, and downstream single-locus studies with RNA-seq, we further characterized cis-acting gene regulatory differences, including changes to FOS, TNIK, FOSL2, and MAZ, that influence neurogenesis and neuronal maturation. This study identifies specific genomic changes that may contribute to human neural specializations and provides a general framework for understanding genetic differences that underlie human traits.

Study phs004053

DNA methylation and transposable element landscapes define human regulatory T cells in tissues and identify their blood recirculating counterpart

Regulatory T cells (Treg cells) in tissues can perform immunoregulatory and tissue-regenerative functions. Despite these important tasks, human-tissue Treg cells lack understanding, specifically, the epigenetic basis of their differentiation as well as re-circulating tissue-Treg cells are incompletely understood. Here, we performed genome-wide DNA methylation analysis of human Treg cells from skin and blood and embedded this in a multi-omic epigenetic framework including chromatin accessibility and gene-expression. We thereby revealed novel epigenetic programs defining human skin Treg cell differentiation and delineated how these are present on the different epigenetic levels. We discovered that transposable elements are an integral constituent of the demethylation landscape in skin Treg cells. Based on TCR-sequencing and DNA demethylation homologies, our data unveil that blood CCR8+ Treg cells are recirculatory human tissue-Treg cells. Our data provide novel insights in human tissue-Treg biology, required to harness these cells for therapeutic avenues.

Study EGAS50000000738

A Translational, Pharmacodynamic and Pharmacokinetic Phase IB Clinical Study of Everolimus in Resectable Non-Small Cell Lung Cancer

This phase IB clinical trial studied the pharmacodynamic changes induced by everolimus in patients with previously untreated, resectable non small cell lung cancer. Using a combination of in vivo and ex vivo assessments with FDG PET, immunohistochemistry and genomic assays, evidence of mTOR pathway perturbation was assessed in patients treated with everolimus, an allosteric mTOR inhibitor. Untreated patients served as controls for comparison. Key results from this work include a dose-dependent biologic effect of everolimus, signal of activity in RAS mutant tumors as well as near complete metabolic and pathologic response in a case of sarcomatoid lung cancer. These findings represent novel translational insights that can guide future development of mTOR inhibitors in lung cancer and other tumor types. Additionally, metabolic response and anatomic tumor shrinkage observed in a significant proportion of patients following a short of duration of therapy with everolimus suggests potential clinical utility of this agent in carefully-selected lung cancer patients.

Study phs000829

MutWP6__CRUK_Grand_Challenge_Mutographs_of_Cancer__Botseq

The Mutographs project aims to advance our understanding of the causes of cancer through studies of mutational signatures. Led by Mike Stratton, together with Paul Brennan, Ludmil Alexandrov, Allan Balmain, David Phillips and Peter Campbell, this large-scale international research endeavour was awarded a Cancer Research UK Grand Challenge. Within Mutographs, work lead by the Sanger Institute will investigate whether detection of somatic mutations and mutational signatures in circulating white blood cells can be developed into a practical, generic system for surveying and monitoring multiple different endogenous and exogenous exposures, providing an ‘observatory’ on somatic mutational processes in humans. Whole genome sequences are generated at the Wellcome Sanger Institute (Illumina HiSeqX). Somatic mutational signatures are subsequently extracted by non-negative matrix factorisation methods. Through an enhanced understanding of cancer aetiology, Mutographs unprecedented effort is anticipated to outline modifiable risk factors, lead to new approaches to prevent cancer, and provide opportunities to empower early detection, refine high-risk groups and contribute to further therapeutic development.

Study EGAS00001004330

High Resolution Maps of the HeLa 3D Genome Using Hi-C

We use in situ Hi-C to probe the three-dimensional architecture of genomes, constructing haploid and diploid maps of nine cell types (including HeLa). The densest, in human lymphoblastoid cells, contains 4.9 billion contacts, achieving 1-kilobase resolution. We find that genomes are partitioned into contact domains (median length, 185kb), which are associated with distinct patterns of histone marks and segregate into six subcompartments. We identify ~10,000 loops. These loops frequently link promoters and enhancers, correlate with gene activation, and show conservation across cell types and species. Loop anchors typically occur at domain boundaries and bind CTCF. CTCF sites at loop anchors occur predominantly (>90%) in a convergent orientation, with the asymmetric motifs 'facing' one another. The inactive X-chromosome splits into two massive domains and contains large loops anchored at CTCF-binding repeats. The data for the other (non-HeLa) cell types has been uploaded to GEO.

Study phs001010

PD-1 antibody-bound progenitor-exhausted CD8+ T cells in lymph nodes boost PD-1-blockade anti-tumor immunity in gastrointestinal cancer

While progenitor-exhausted T cells (Tpex) expressing TCF1 and PD-1 are crucial for the therapeutic effect of immune checkpoint inhibitors (ICIs; therapeutic anti-PD-1 antibodies), the dynamics of ICI-bound Tpex are not fully understood. In this study, we investigated ICI-bound T cells in detail using combined sequencing analysis at the single cell level. By analyzing samples from gastrointestinal cancer patients with or without ICI treatment, we found that Tpex were enriched in proximal lymph nodes (LNs) and proliferated at a high rate after ICI treatment. Importantly, ICI high-bound Tpex in LNs shared T-cell receptor clonotypes with intratumoral exhausted CD8+ T cells (Tex), suggesting their migration to tumor sites after ICI treatment. These findings indicate that ICIs initially target PD-1+CD8+ Tpex in LNs, prompting their proliferation. Subsequently, these cells migrate to tumors and differentiate into Tex, thereby exerting anti-tumor immunity.

Study JGAS000720

Deciphering craniopharyngioma subtypes: Single-cell analysis of tumor microenvironment and immune networks

Craniopharyngiomas, including both adamantinomatous (ACP) and squamous papillary (PCP) types, present significant challenges in treatment due to their proximity to critical pituitary structures. In this study, we conducted a single-cell RNA analysis to examine the tumor microenvironments (TME) of ACP and PCP. Single-cell clustering revealed a wide range of cell types, which were further categorized based on gene expression patterns. For ACP, these categories included developing epithelia, calcification, and immune response, while PCP showed developing epithelia, cell cycle, and immune response as prominent categories. Subclustering analysis unveiled different types of immune cells in both ACP and PCP TMEs, with specific patterns of immune responses. Interestingly, smaller tumors were associated with particular immune cell ratios. Furthermore, we identified specific cell-to-cell interactions within the tumor cells. In conclusion, our study has led to the development of a comprehensive cell atlas, shedding light on the molecular characteristics and intricate interplay of immune cells within the TMEs of ACP and PCP.

Study JGAS000722

Single Cell Transcriptional Analysis of Human Adenoids Identifies Molecular Features of Airway Microfold Cells

We aimed to characterize the cellular composition and molecular features of the human adenoid, a mucosa-associated lymphoid tissue located in the upper airway, with a focus on epithelial populations involved in immune surveillance. To this end, we performed single-nucleus RNA sequencing (snRNA-seq) on adenoid tissue obtained from 6 human donors (age 2 – 14; 3 males and 3 females) undergoing routine adenoidectomy. The donor cohort includes clinically annotated samples with no known immunodeficiency or chronic airway disease.Our analysis uncovered distinct epithelial populations, including transcriptionally defined immature and mature microfold (M) cells, and a previously unrecognized interferon-stimulated epithelial population enriched for antiviral response genes, which we term WISP cells (Waldeyer's ring Interferon-Stimulated Population). We validated key transcriptomic findings through multiplex immunofluorescence microscopy in independent donor tissues, confirming the spatial localization of WISP and M cells and their predicted interactions with specific immune subsets.

Study phs004103

CLL Genome

The Chronic Lymphocytic Leukemia (CLL) Genome Project aims to identify genetic alterations involved in the development and progression of the CLL, which are still unknown, with the objective of generating a comprehensive catalogue of genetic alterations in 500 independent tumours. The CLL Genome Project, as a contributing member of the International Cancer Genome Consortium (ICGC), has the purposes of creating diagnostic tools, discovering therapeutic targets and developing new strategies that will allow a customized therapy for CLL in order to make it more precise and effective. This study consists of two datasets. EGAD00001000023 described in the Nature paper (2011), Whole-genome sequencing identifies recurrent mutations in chronic lymphocytic leukaemia, and the dataset EGA00001000044 & & EGAD00001000083 described in the Nature (2011) paper, Exome sequencing identifies recurrent mutations of the splicing factor SF3B1 gene in chronic lymphocytic leukemia.Additional data generated within the ICGC-CLL genome project can be found in studies EGAS00001000374 and EGAS00001001306

Study EGAS00000000092

Hofer et al., A specific subpopulation of cancer-associated fibroblasts promotes resistance to chemotherapy in triple-negative breast cancer by upregulating G0S2 protein

Chemotherapy is the standard of care for patients with triple-negative breast cancer (TNBC), but the mechanisms of chemoresistance remain poorly understood. Here, we investigated the role of cancer associated fibroblasts (CAFs) in the chemotherapy response of TNBC, by combining in vivo analyses of TNBC patients with ex vivo cancer modeling, using tumor-on-chip (ToC) technology. Transcriptomic analysis revealed that the proportion of a specific CAF population, the extracellular matrix-producing myofibroblasts (ECM-myCAFs), is reduced after chemotherapy in chemo-sensitive, but not in chemo-resistant TNBC patients. In ToC devices, primary ECM-myCAFs promoted TNBC cell survival under Doxorubicin and Paclitaxel treatment. The mechanism of chemoresistance was elucidated by using single-cell RNA sequencing, advanced cell imaging and functional assays: ECM-myCAFs upregulate the G0/G1 switch 2 (G0S2) protein in TNBC cells, via activation of SRC family kinases. Altogether, our work identifies G0S2 as a new player in CAF mediated chemotherapy resistance in TNBC.

Study EGAS50000000886

Tumor inflammation and mutational burden are differentially associated with response to nivolumab or nivolumab plus ipilimumab in metastatic colorectal cancer

Nivolumab alone and in combination with ipilimumab demonstrated durable clinical benefit in patients with previously treated microsatellite instability-high/mismatch repair-deficient metastatic colorectal cancer in the phase 2 CheckMate 142 study. Exploratory biomarker analyses of tumor and microbiome samples from CheckMate 142 were performed to evaluate associations between various biomarkers and the efficacy of nivolumab monotherapy and nivolumab plus ipilimumab combination in these patients. Higher expression of inflammation-related gene expression signatures was associated with improved response per investigator assessment and survival benefit with nivolumab monotherapy. In contrast, higher tumor mutational burden, tumor indel burden and degrees of microsatellite instability were associated with improved response per investigator assessment and survival benefit with nivolumab plus ipilimumab. While interpretation is limited by the exploratory nature of these analyses, they suggest that tumor antigenicity rather than baseline tumor inflammation might be important for the combinatorial efficacy. Validation of these findings in larger, randomized studies is necessary.

Study EGAS50000000416

Maturation of Human Intestinal Epithelial Cell Layers Fortifies the Apical Surface against Salmonella Attack

Pathogen invasion of intestinal epithelial cells (IECs) is a key gut infection event. The dynamics of this process in intact epithelia and the factors governing IEC susceptibility remain underexplored. We present a resource for live-cell infection imaging in human enteroid-/colonoid-derived IEC layers, across maturation states and in the presence or absence of soluble mucus production. Utilization of this resource shows how human IEC maturation fortifies the apical surface against invasion by Salmonella Typhimurium (S.Tm). Immature IEC layers appear permissive to S.Tm invasion, but maturation towards an enterocyte/colonocyte phenotype reduces the susceptibility by up to tenfold. This shift couples to downregulated expression of actin regulatory proteins exploited by the pathogen, an increased dependence on the S.Tm effector SipA, and the build-up of the apical IEC glycocalyx linked to surface-attached mucins like MUC13 and nullifiable by StcE-enzyme treatment. This underscores how the maturation state of human IECs governs susceptibility to bacterial invasion.

Study EGAS50000001241

WGS analysis of Japanese liver cancer

Liver cancer is prevalent worldwide, mainly associated with virus infection, and its underlying etiology and genomic structure are heterogeneous. Here we provide a whole-genome landscape of somatic alterations in 300 Japanese liver cancers. Our comprehensive analysis elucidated point mutations in non-coding regions, structural variants (SVs), and virus integrations, in addition to coding mutations, and demonstrated new mutational signatures related with liver carcinogenesis, novel recurrently mutated coding and non-coding regions such as lincRNA NEAT1/MALAT1, promoters, CTCF binding sites, and regulatory regions. SV analysis found a significant association with replication timing, and revealed that known cancer genes (CDKN2A, CCND1, APC, and TERT) and new cancer genes (ASH1L, NCOR1, MACROD2) were recurrently affected by SVs, leading to altered expression of nearby genes. These results emphasize the value of whole genome sequencing analysis to discover cancer driver mutations and to understand comprehensive molecular profiles of liver cancer, especially for SVs and non-coding mutations.

Study JGAS000151

Parent-of-origin dependent DNA methylation and gene expression in the human placenta

DNA methylation is globally reprogrammed after fertilization and the parental genomes have similar DNA methylation profiles after implantation except at the germline differentially methylated regions (gDMRs). We, and others, have previously shown that there are a large number of transient gDMRs in human blastocysts, whose differential methylation is lost in embryonic tissues after implantation. In this study we employed genome-wide allelic DNA methylation analyses of highly purified trophoblast cells from human placentas. ~40% of the transient-in-embryo gDMRs maintained their parent-of-origin-dependent biased allelic methylation. RNA sequencing-based allelic expression analyses revealed that some of the placental-specific gDMRs were associated with novel imprinted genes. This approach identified the first examples of X-linked gDMRs specific to the placenta. These findings highlight the unique regulation of allelic DNA methylation in the human placenta, which is important for understanding normal placental development and the pathogenesis of pregnancy complications.

Study JGAS000038

A tumor-associated photoreceptor signature unifies distinct central nervous system malignancies

Pineoblastoma is a clinically aggressive childhood brain tumor composed of distinct molecular subgroups with divergent driver genes, demographics, and clinical outcomes. To identify developmental origins and mechanisms governing disease pathogenesis, we derive single-cell transcriptomes from pineal parenchymal tumors, aligning malignant cells with our atlas of pineal gland development to retrace cellular origins. Integrative computational analyses maps pineoblastoma origins to transient cycling pinealocyte progenitors during development. Lineage-specific perturbation of suspected drivers in the early pineal gland yields preclinical models representative of consensus molecular subgroups. Multi-omic characterization of patient tumors and these models uncovers a tumor-associated photoreceptor signature common to pineoblastoma, retinoblastoma, and Group 3 medulloblastoma. Transcriptional activity of this signature within respective cellular origins establishes a developmental basis for molecular similarities between entities. Photoreceptor signature constituents are selective dependencies across these anatomically distinct central nervous system malignancies, motivating future studies evaluating developmentally encoded programs of malignancy as potential therapeutic liabilities.

Study EGAS50000001457

Single Cell RNA Transcriptomics of Mantle Cell Lymphoma Reveals the Presence of Treatment-Resistant Subclones at the Time of Diagnosis

Mantle cell lymphoma is a chronically relapsing B cell neoplasm characterized by clonal heterogeneity. We implemented single cell RNA sequencing of paired tumor samples from four patients with an aggressive nodal MCL at diagnosis and after failure of standard immunochemotherapy. Clustering the cells based on the inferred CNVs showed small subclones present at diagnosis with a CNV profile similar to the major subclone at relapse. Comparison of these subclones to major subclones present at diagnosis revealed 119 upregulated pathways common for the four patient with an aggressive MCL, including NF-kappaB and PTEN signaling pathways. Additionally, we sequenced a patient with an indolent to blastoid MCL transformation with intestinal tissue involvement. In contrast to other compartments at relapse, the cells in the intestine showed strikingly different CNV profile and presence of new driver mutations including NOTCH1. In conclusion, our study demonstrates that scRNAseq can potentially detect therapy resistant subclones at diagnosis.

Study EGAS50000000825

Transcriptome changes in circulating immune cells of critical COVID-19 patients predict a specific metabolic and epigenetic imprint

The progression to severe COVID-19 arises predominantly from a dysregulated host immune response, although the underlying regulatory mechanisms still remain partially elusive. This limits a prompt prediction of disease progression and restrains our understanding of “long COVID”. Here, we analyzed the transcriptomes of peripheral blood mononuclear cells collected from COVID-19 patients experiencing different degrees of the disease and control patients. In critical COVID-19 patients, we found an altered regulatory network involving microRNAs, long non-coding RNAs, and coding genes that control mRNA translation-related genes, epigenetics, and metabolism. We also observed an upregulation of tRNA aminoacylation genes and increased expression of coding genes enriched for the cognate amino acids. Collectively, our findings indicate a broad perturbation of the gene expression landscape that characterizes the aberrant host immune response in critical COVID-19 patients and is potentially coordinated by alterations in microRNA expression and tRNA metabolism.

Study EGAS50000000965

STimage: Robust and interpretable prediction of gene markers and cell types from spatial transcriptomics data

Spatial transcriptomics (ST) links tissue morphology with gene expression values, opening new avenues for digital pathology. Deep learning models are used to predict gene expression or classify cell types directly from images, offering significant clinical potential but still requiring improvements in interpretability and robustness. We present STimage as a comprehensive suite of models to predict spatial gene expression and classify cell types directly from standard H\&E images. STimage enhances robustness by estimating gene expression distributions and quantifying both data-driven (aleatoric) and model-based (epistemic) uncertainty using ensemble approach with foundation models. Interpretability is achieved through attribution analysis at single-cell resolution integrated with histopathological annotations, functional genes, and latent representations. We validated STimage across diverse datasets, demonstrating its performance across various platforms. STimage-predicted gene expression can stratify patient survival and predict drug response. By enabling molecular and cellular prediction from routine histology, STimage offers a powerful tool to advance digital pathology.

Study EGAS50000001503

Adjuvant nivolumab in resected esophageal or gastroesophageal junction cancer: exploratory biomarker analyses from CheckMate 577

Adjuvant nivolumab demonstrated a significant improvement in disease-free survival (DFS; primary endpoint) versus placebo in patients with resected esophageal or gastroesophageal junction cancer and residual pathologic disease following neoadjuvant chemoradiotherapy (CRT) in the phase III CheckMate 577 study, leading to global approval and widespread adoption. Exploratory biomarker analyses were performed using whole-exome sequencing, RNA sequencing, and immunohistochemistry. Hazard ratios for DFS favored nivolumab versus placebo in patients with higher inflammation and proliferation gene expression signature scores; lower M2 macrophage, endothelial, and stromal GES scores; and higher densities of CD3+/CD8- T cells and natural killer cells. Assessments of pre-CRT and post-CRT tumor tissue found post-CRT increases in programmed death ligand 1 combined positive score in 51% of patients, which appeared to be associated with greater DFS benefit. Through these analyses, we identified patient subpopulations that appear to derive improved DFS benefit from adjuvant nivolumab in this setting.

Study EGAS50000001663

Whole_genome_sequencing_in_a_multiplex_Crohn_s_disease_family

In 2009 we identified a four-generation family with over 700 members and 41 affected with Crohn's disease (CD). At the time we sequenced the exome of 6 affected individuals but did not identify any coding variants which appear to explain the high prevalence of disease. Since then we have collected DNA from a large number of additional family members, genotyped linkage arrays on the entire family to refine genomic regions shared by identity by descent and genotyped affected and unaffected members at known CD risk loci identified by Genome Wide Association Studies (GWAS). These analyses have confirmed that a significant unexplained excess of disease remains after accounting for all known genetic factors, and that several regions of the genome are shared by a large fraction of affected individuals. We therefore perform whole genomes sequencing from 8 individuals which will allow us to impute the complete sequence of nearly all the members of the two largest and most severely affected branches of the family.

Study EGAS00001000060

Impact of mutational profiles on response of primary oestrogen receptor-positive breast cancers to oestrogen deprivation

Presurgical studies allow study of the relationship between mutations and response of estrogen receptor positive (ER+) breast cancer to aromatase inhibitors (AIs) but have been limited to small biopsies. Here in Phase I of this study, we perform exome sequencing on baseline, surgical core-cuts and blood from 60 patients (40 AI treated, 20 Controls). In poor responders (based on Ki67 change) we find significantly more somatic mutations than good responders. Subclones exclusive to baseline or surgical cores occur in approximately 30% of tumours. In Phase II we combine targeted sequencing on another 28 treated patients with Phase I. We find six genes frequently mutated: PIK3CA, TP53, CDH1, MLL3, ABCA13 and FLG with 71% concordance between paired cores. TP53 mutations are associated with poor response. We conclude that multiple biopsies are essential for confident mutational profiling of ER+ breast cancer and TP53 mutations are associated with resistance to oestrogen deprivation therapy.

Study EGAS00001001940

Inferring expressed genes by whole-genome sequencing of plasma DNA

The analysis of cell-free DNA (cfDNA) in plasma represents a rapidly advancing field in medicine. cfDNA consists predominantly of nucleosome-protected DNA shed into the bloodstream by cells undergoing apoptosis. We performed whole-genome sequencing (WGS) of plasma DNA and identified two discrete regions at transcription start sites (TSS) where the nucleosome occupancy results in different read-depth coverage patterns in expressed and silent genes. By employing machine learning for gene classification we found that the plasma DNA read depth patterns from healthy donors reflected the expression signature of hematopoietic cells. In cancer patients with metastatic disease, we were able to classify expressed cancer driver genes in regions with somatic copy number gains with high accuracy. We could even determine the expressed isoform of genes with several TSSs as confirmed by RNA-Seq of the matching primary tumor. Our analyses provide functional information about the cells releasing their DNA into the circulation.

Study EGAS00001001754

Inactivation of TGFβ receptors in stem cells drives cutaneous squamous cell carcinoma - 30 whole exomes

Melanoma patients treated with oncogenic BRAF inhibitors can develop cutaneous squamous cell carcinoma (cSCC) within weeks of treatment, driven by paradoxical RAS/RAF/MAPK pathway activation. Here, we identify frequent TGFBR1 and TGFBR2 mutations in human vemurafenib-induced skin lesions and in sporadic cSCC. Functional analysis reveals these mutations ablate canonical TGFβ Smad signaling which is localised to bulge stem cells in both normal human and murine skin. MAPK pathway hyperactivation (through BrafV600E or KrasG12D knockin) and TGFβ signaling ablation (through Tgfbr1 deletion) in LGR5+ve stem cells enables rapid cSCC development in the mouse. Mutation of Tp53 (which is commonly mutated in sporadic cSCC) coupled with Tgfbr1 deletion in LGR5+ve cells also results in cSCC development. These findings indicate that LGR5+ve stem cells can act as cells of origin for cSCC and that RAS/RAF/MAPK pathway hyperactivation or Tp53 mutation, coupled with loss of TGFβ signaling, are driving events of skin tumorigenesis.

Study EGAS00001001892

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