23217 results for "ega"

in 49.09 milliseconds.

• Genomic determinants of response and resistance to inotuzumab in B-ALL

  Inotuzumab Ozogamicin (InO) is an antibody-drug conjugate which delivers calicheamicin to CD22-expressing cells. In a retrospective cohort of InO treated B-cell acute lymphoblastic leukemia (B-ALL) patients, we sought to understand the genomic determinants of response to InO. Acquired CD22 mutations were observed in 11% (3/27) of post-InO relapsed samples. CD22 mutation types were diverse (frameshift, nonsense, missense and stoploss) and we identified multiple mechanisms of mutation induced CD22 escape, including protein truncation, protein destabilization, and epitope alteration. Accelerated acquisition of mutations by error-prone DNA damage repair could drive CD22 mutation and escape. Acquired loss-of-function mutations in TP53, ATM and CDKN2A were observed, suggesting compromise of the G1/S DNA damage checkpoint as a mechanism of evading InO-induced apoptosis. In conclusion, genetic alterations modulating CD22 expression and DNA damage response influence InO efficacy. The diverse mechanisms of CD22 escape advocates for a refined approach for monitoring CD22-targeted therapy.

  Study EGAS50000000067

• Pyjacker identifies enhancer hijacking events in acute myeloid leukemia including MNX1 activation via deletion 7q

  Acute myeloid leukemia with complex karyotype (ckAML) is characterized by high genomic complexity, including frequent TP53 mutations and chromothripsis. We hypothesized that the numerous genomic rearrangements could reposition active enhancers near proto-oncogenes, leading to their aberrant expression. We developed pyjacker, a computational tool for the detection of enhancer hijacking events, and applied it to a cohort of 39 ckAML samples. Pyjacker identified motor neuron and pancreas homeobox 1 (MNX1), a gene aberrantly expressed in 1.4% of AML patients, often as a result of del(7)(q22q36) associated with hijacking of a CDK6 enhancer. MNX1-activated cases show significant co-occurrence with BCOR mutations and a gene signature shared with t(7;12)(q36;p13) pediatric AML. We demonstrated that MNX1 is a dependency gene, as its knockdown in a xenograft model reduces leukemia cell fitness. In conclusion, enhancer hijacking is a frequent mechanism for oncogene activation in AML.

  Study EGAS50000000743

• A single-chain derivative of the integrin β1-activating TS2/16 antibody potentiates organoid growth in Matrigel and Collagen hydrogels.

  Culturing epithelial organoids from Adult Stem Cells (ASCs) requires interaction of their β1-integrins with extracellular matrix (ECM) components such as laminin or collagen. Matrigel and BME® (extracts from Engelbreth-Holm-Swarm tumor cells grown in the mouse abdomen) are a popular source of ECM proteins. Yet, these preparations are costly and subject to batch-to-batch variation due to animal-derived contaminations. Here, we describe a single chain version (scFv) of antibody TS2/16, allosterically activating integrin β1 function in organoids. Addition of 5 nM of monomeric scFv to organoid medium results in up to 5-fold higher yields of organoids in Matrigel/BME®. In addition, scTS2/16 generates 6-7-fold higher yields of intestinal organoids in collagen-I hydrogel, when grown both in 3D and in 2D. Collagen is well-defined, available at clinical grade, and in combination with scTS2/16, will enable the clinical use of gastrointestinal organoids.

  Study EGAS50000001113

• Spatial Transcriptomics Uncovers Tumor Microenvironment-Based Subtypes in Invasive Lobular Carcinoma

  Invasive lobular carcinoma (ILC) is the second most common histological subtype of breast cancer (BC); however, little is known about its tumor microenvironment (TME). Here, we investigated the spatial architecture of 43 hormone-receptor-positive, HER2-negative (HR+/HER2-) primary ILC samples, using spatial transcriptomics and detailed morphological annotation. By integrating morphology, spatial, and single-cell data, we mapped TME-related cell types, exploring their proximity to tumor cells and their enrichment in specific compartments. Clustering of spatial transcriptomics spots revealed significant inter- and intra-tumor heterogeneity, identifying pathways and cell types linked with disease outcomes. Morphological and gene expression data were finally integrated with a multimodal approach, leading to the identification of 4 new ILC subtypes based on TME heterogeneity. By using derived, specific gene expression signatures, these subtypes were identified and validated in external bulk RNA-seq/microarray datasets (SCAN-B and METABRIC), where differences in prognosis emerged.

  Study EGAS50000001001

• Direct genetic transformation bypasses tumor-associated DNA methylation alterations

  Tumors represent dynamically evolving populations of mutant cells, and many advances have been made in understanding the biology of their progression. However, key unresolved questions remain about the conditions that support their initial transformation, which cannot be easily captured in patient populations but are instead modeled using transgenic cellular or animal systems. Here, we used extensive patient atlas data to define common features of the tumor DNA methylation landscape as they compare to healthy human cells and used this benchmark to screen 21 engineered human and mouse models for their ability to reproduce these patterns. Notably, we find that genetically induced cellular transformation can trigger global changes in DNA methylation levels that are consistent with extensive proliferation but rarely recapitulate the widespread de novo methylation of Polycomb targets as found in clinical samples. Our results raise pertinent questions about the relationship between genetic and epigenetic aspects of tumorigenesis and provide an important molecular reference for evaluating existing as well as newer tumor models.

  Study EGAS50000000902

• High-grade B-cell lymphoma, not otherwise specified: an LLMPP study

  Molecular characterization of high-grade B-cell lymphoma, not otherwise specified (HGBCL-NOS), is hindered by its rarity, evolving definition, and poor diagnostic reproducibility. To address this challenge, we analyzed 92 HGBCL-NOS tumors collected across Lymphoma/Leukemia Molecular Profiling Project sites. These tumors were profiled using whole-genome sequencing (WGS) or whole-exome sequencing (WES) to identify somatic mutations, WGS or low-pass WGS to detect copy number alterations, targeted capture sequencing to assess MYC and BCL2 structural variants, and RNA sequencing. The genetic features of HGBCL-NOS were compared to those of diffuse large B-cell lymphoma (DLBCL-NOS) and EBV-negative adult Burkitt lymphoma (BL). DLBCL-NOS tumors underwent targeted capture sequencing using a panel of 125 genes recurrently mutated in aggressive B-cell lymphomas. BL biopsies were drawn from the Burkitt Lymphoma Genome Sequencing Project and had available WGS (dbGaP Study Accession: phs000527.v18.p6).

  Study EGAS50000000932

• 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

• Identifying genetic variants that alter TCR usage in the peripheral repertoire

  The relationship between genetic variation and CD8+ T-cell receptor (TCR) repertoire usage in patients receiving Immune Checkpoint Blockade (ICB) therapy for cancer is unexplored. We have conducted a genome-wide and human leukocyte antigen (HLA)-focused analysis of CD8+ T-cell TCR repertoire to identify genetic determinants of variable gene (V-gene) and CDR3 K-mer usage from samples taken prior to and after ICB (n=250). We identify 11 cis and 10 trans V-gene associations, primarily to the MHC, that meet genome-wide significance. TCR clones containing HLA associated V-genes were less stable across treatment, whilst at the single-cell level, genetically associated clones demonstrate subset enrichment and increased tumor reactivity expression profiles. Notably, patients with HLA-matched TCR clones demonstrate improved overall survival. Our work indicates a complex relationship between genotype and TCR repertoire in the context of ICB treatment, with novel implications for understanding factors relating to therapeutic response and patient outcomes.

  Study EGAS00001008189

• 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

• Sensitive neoantigen discovery by real-time mutanome-guided immunopeptidomics - WES

  Targeting cancer-specific HLA-peptide complexes is a promising immunotherapy approach, with mutated neoantigens offering high value for their immunogenicity and cancer-specificity. Selecting immunogenic targets requires personalized prioritization of cancer-specific immunopeptides. Mass spectrometry (MS)-based immunopeptidomics supports this process by directly identifying cancer-specific antigens and informing global presentation patterns to refine immunogenicity predictions. Clinical pipelines, however, must balance global depth and target sensitivity compounded by low input samples and time constraints. Here, we present NeoDiscMS, an extension of the NeoDisc pipeline, enabling personalized immunopeptidomics data acquisition. By leveraging real-time NGS-guided spectral acquisitions, NeoDiscMS maximizing sensitivity with minimal loss of global depth. NeoDiscMS improves TAA-derived peptide detection up to 20% and enhances neoantigen identification confidence compared to the clinical gold standard method. Designed for effectiveness and ease of use, it requires minimal effort for implementation. NeoDiscMS advances personalization in clinical antigen discovery by enabling more sensitive neoantigen detection while seamlessly integrating into existing workflows.

  Study EGAS50000000976

• Dual inhibition of FLT3 and BCL-2 is effective in preclinical models of BCL11B-activated lineage ambiguous leukemia

  Aberrant activation of BCL11B (“BCL11B-a”) defines a subtype of lineage ambiguous leukemias with T-lymphoid and myeloid features, co-occurring activating FLT3 mutations, and a stem/progenitor immunophenotype and gene expression profile. As with other lineage ambiguous leukemias, optimal treatment is unclear and there are limited targeted therapeutic options. Here, we investigated the efficacy of BCL-2 and FLT3 inhibition with venetoclax and gilteritinib, respectively, in preclinical models of BCL11B-a leukemia. Despite variation in response to single agent therapies, the combination of venetoclax plus gilteritinib was highly effective in all models evaluated. BH3 profiling and single cell RNA-seq analysis suggests that resistance to venetoclax and/or gilteritinib monotherapies is due to the tumor-intrinsic activity of BCL-xL and/or MCL-1 prior to drug treatment. These data support clinical evaluation of venetoclax in combination with gilteritinib in BCL11B-a lineage ambiguous leukemias.

  Study EGAS50000000978

• Single cell RNA sequencing of human embryonic forebrain after slice culturing for between four weeks and one month

  With the aim of verifying normal tissue development in our Organotypic Timelapse recording with Transcriptomic Readout (OTTR) live tissue imaging method, we performed single cell RNA sequencing in organotypic slice cultures containing labelled cells from virally delivered ubiquitous Enhanced yellow fluorescent protein (EYFP)-expression. Human fetal cortices of PCW 7.5-10.5 were cut into strips along the dorso-ventral axis and directly placed en face, ventricular side down, on PTFE culturing membranes. To assess tissue health with our culturing method, we performed single cell RNA-seq analysis of the cortical explants (using adjacent slices from the same samples subjected to timelapse imaging). We cultured these control slices for four days in vitro (mimicking the start of a live imaging experiment after lentiviral infection and expression of EYFP), 11 days in vitro (corresponding to the end of one week of live imaging), and for two weeks and one month in vitro.

  Study EGAS50000001185

• 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

• 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

• ucfDNA workflows for molecular profiling of malignant disease

  Urinary cell-free DNA (ucfDNA) is a promising liquid biopsy analyte obtained by a non-invasive sampling method, particularly valuable in urological cancers due to the proximity of biofluids to the tumor site. However, extremely high fragmentation and low abundance of ucfDNA pose significant analytical challenges. Improper handling and storage can severely affect ucfDNA quality, necessitating optimized pre-analytical workflows for clinical applications. We evaluated multiple pre-analytical workflows, including urine stabilization approaches against unstabilized urine samples. Our results demonstrated that without stabilization, ucfDNA degraded rapidly and minimal quantities remaining after 72 hours. In contrast, urine stabilization preserved ucfDNA integrity, enabling successful downstream analyses, including digital PCR and next-generation sequencing, for mutation detection in cancer-related genes and genome wide copy number profiling. These findings underscore the critical role of stabilization for a reliable ucfDNA analysis and highlight its potential in molecular diagnostics as a complementary tool to plasma-based liquid biopsies.

  Study EGAS50000001093

• Processing of tissue and cfDNA samples of CRC patients using Active-seq

  In this study, we have developed a novel technology called Active-Seq (Azide Click Tagging for In Vitro Epigenomic sequencing), a base conversion-free technology used to profile the DNA methylation status of a sample, based on the isolation of DNA containing unmodified CpG sites using a mutated bacterial methyltransferase enzyme and a synthetically prepared cofactor analogue. We procured samples from colorectal cancer (CRC) patients including tumour tissue as well as normal adjacent tissues. The data enabled us to identify CRC-specific markers that could then be used to track and monitor the presence of tumour DNA in cell-free DNA plasma (cfDNA) samples procured in the same patients. The FASTQ files of all the colorectal cancer tissues, normal adjacent tissues as wells as the cfDNA samples are available in this submission. The data made available in this study have been used to outline an approach for tumour-informed disease profiling in colorectal cancer cfDNA samples using Active-Seq.

  Study EGAS50000001226

• Dynamic human admixture histories over the past ~1,300 years at the northern Himalayan frontier

  Archaeological and paleogenomic evidence from the Tibetan Plateau and high-altitude Central Himalayas suggest biocultural connections with each other and with lowland East, Central, and South Asia. However, genetic histories at the northern frontier of the Indian Himalayas, which is geographically more proximal to Central and lowland South Asia, remain underexplored. We analyzed genome-wide data from 7 ancient (~2300 to 100 years old) and 10 present-day individuals from the northern Indian Himalayas and one ~3370-year-old individual from the Central Himalayas in Nepal. Ancient and present-day individuals from the northern Himalayas predominantly have Tibetan-related genetic ancestry, likely the source of high-altitude adaptive variants in these individuals, with substantial Steppe-related genetic ancestry that is observed in all individuals dating between ~1300 years and present day. In addition, some present-day individuals have lowland South Asian admixture. Our analyses reveal a dynamic interplay between genetic admixture and continuity in the northern Himalayas.

  Study EGAS50000001342

• Spatial Dynamics of the Developing Human Heart

  Heart development relies on a topologically defined interplay between diverse cardiac cells. We finely curated spatial and single-cell measurements with high-resolution imaging-based transcriptomics validation to explore spatial dynamics during early human cardiogenesis. Analyzing almost 80,000 individual cells and 70,000 spatially barcoded tissue regions between the 5.5th and 14th postconceptional weeks, we identified 31 coarse- and 72 fine-grained cell states and mapped them to highly resolved cardiac cellular niches. We provide novel insight into the development of the cardiac pacemaker-conduction system, heart valves, and atrial septum, and decipher heterogeneity of the hitherto elusive cardiac fibroblast population. Furthermore, we describe the formation of the cardiac autonomic innervation and present the first spatial account of chromaffin cells in the fetal human heart. Our study, supported by an open-access, spatially centric interactive viewer, delineates the cellular and molecular architecture of the developing heart, offering links to genetic causes of heart disease.

  Study EGAS50000001122

• Spatial Dynamics of the Developing Heart (single-cell)

  Heart development relies on a topologically defined interplay between diverse cardiac cells. We finely curated spatial and single-cell measurements with high-resolution imaging-based transcriptomics validation to explore spatial dynamics during early human cardiogenesis. Analyzing almost 80,000 individual cells and 70,000 spatially barcoded tissue regions between the 5.5th and 14th postconceptional weeks, we identified 31 coarse- and 72 fine-grained cell states and mapped them to highly resolved cardiac cellular niches. We provide novel insight into the development of the cardiac pacemaker-conduction system, heart valves, and atrial septum, and decipher heterogeneity of the hitherto elusive cardiac fibroblast population. Furthermore, we describe the formation of the cardiac autonomic innervation and present the first spatial account of chromaffin cells in the fetal human heart. Our study, supported by an open-access, spatially centric interactive viewer, delineates the cellular and molecular architecture of the developing heart, offering links to genetic causes of heart disease.

  Study EGAS50000001029

• 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

• T cell receptor repertoire in cell-free DNA as a proxy for tumor infiltrates in patients treated with pembrolizumab

  Profiling tumour and systemic T-cell receptor (TCR) repertoires can identify features associated with clinical benefit of cancer patients on immune checkpoint blockade therapy. This study reports on diversity and specificity analysis of TCR sequences from 59 tumor, 306 peripheral blood (PBMC), and 73 cell-free DNA (cfDNA) samples from 81 patients with solid tumors treated with pembrolizumab. This analysis reveals that head and neck carcinomas have significantly lower PBMC diversity and shorter persistence of pembrolizumab-induced diversification compared to other cancers. Using GLIPHII (Grouping Lymphocyte Interactions with Paratope Hotspots), we find that tumor-derived clonotypes form non-microbial specificity signatures that are shared across patients and cancer types. Tumor-derived clonotypes are enriched in cfDNA compared to PBMCs, despite the diversity of cfDNA TCR repertories being two orders of magnitude lower than PBMCs. TCRs shared between tumors and cfDNAs persist in PBMCs beyond 50 weeks of treatment, suggesting cfDNA captures clonotypes contributing to anti-tumor immune surveillance.

  Study EGAS50000001306

• Bulk RNA sequencing of day 2 and day 7 biopsies from the tuberculin skin test in people with latent tuberculosis, and of day 2 biopsies from saline controls

  We used the tuberculin skin test (TST) as human challenge model to study the temporal evolution of the immune response to Mycobacterium tuberculosis (Mtb) antigens in vivo. Study participants comprised healthy HIV seronegative adults, 18-60 years of age. Latent tuberculosis (TB) infection was defined as immune memory for Mtb-specific antigens identified by positive peripheral blood IFNg release assays, but no clinical or radiological evidence of active TB. Two units tuberculin each were injected intradermally into the contralateral forearms of participants. After 2 days (n=216) or 7 days (n=158), 3 mm skin punch biopsies were taken from the injection sites and processed for whole genome transcriptional profiling by bulk RNA sequencing. The time points reflect maximum clinical inflammation (day 2) and maximum T cell infiltration (day 7) of the TST. TST samples were compared to skin biopsies taken two days after control injection of saline in a separate group of individuals (n=33), comprising healthy volunteers as well as patients with active or latent TB, ranging from 18-75 years of age. This dataset includes 407 samples from 256 individuals (n=33 saline, n=223 with Day 2 and/or Day 7 TST). Skin biopsies were collected into RNAlater (Qiagen) for RNA extraction. Total RNA was obtained with the Precellys Evolution homogenizer (Bertin Instruments) and Qiagen RNeasy mini kit. RNA was subjected to DNase treatment to remove contaminating genomic DNA using a TURBO DNA-free kit (Ambion, Life Technologies). The KAPA mRNA HyperPrep Kit (Roche Diagnostics) was used to construct stranded mRNA-Seq libraries from up to 500 ng intact total RNA. Paired-end sequencing was performed on the Illumina Nextseq using the Nextseq 500/550 High Output 75 cycle kit (Illumina). Runs were demultiplexed using bcl2fastq by Illumina.

  Dataset EGAD50000001208

• TONIC-Trial-cfDNA-Project

  Cell-free DNA (cfDNA) is an emerging technology to predict and monitor response to cancer treatment, including immune checkpoint blockade (ICB). However, data on cfDNA dynamics during ICB in metastatic triple negative breast cancer (mTNBC) are limited. While most applications of cfDNA involve assays that focus on mutation detection, mTNBC and multiple other cancer types are driven by copy number alterations (CNAs). We evaluate cfDNA-based copy number profile abnormality (CPA) score as a potential biomarker for monitoring ICB response in mTNBC, analyzing data from 87 patients enrolled in stage 1 and stage 2 of the TONIC-trial. We find significant concordance between cfDNA-based and tissue-based CNA profiles. Additionally, responders show a decrease in CPA scores upon ICB at week 6 (3 cycles of nivolumab). These findings underscore the potential of cfDNA-based CNA dynamics as a non-invasive biomarker for ICB early response assessment in patients with mTNBC.

  Study EGAS50000001308

• Delineation of the heterogeneous molecular landscape of HRS cells and their biological contributions to forming comprehensive TME ecosystems.

  The tissue architecture of classic Hodgkin Lymphoma (CHL) is unique among cancers and characterized by rare malignant Hodgkin and Reed-Sternberg cells that are co-evolving in a complex ecosystem of immune cells in the tumor microenvironment. The lack of a comprehensive systems-level interrogation has hindered the description of disease heterogeneity and clinically relevant molecular subtypes. Here, we employed an integrative, multimodal approach to characterize CHL tumors using malignant cell sequencing, spatial transcriptomics and imaging mass cytometry. We identified four molecular subtypes (CST, CN913, STB, and CN2P) each characterized by distinct clinical features, mutational patterns, malignant cell gene expression profiles, and spatial architecture of immune cell populations. Functional modeling of CSF2RB mutations, a characteristic feature of CST, revealed dysregulated oncogenic signaling and changes in tumor microenvironment crosstalk. These findings highlight the significance of multi-dimensional profiling in elucidating patterns of molecular alterations that drive immune ecosystems and underlie therapeutically exploitable vulnerabilities.

  Study EGAS00001008064

• 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

• Common origin and somatic mutation patterns of composite lymphomas and leukemias

  When two lymphomas occur concurrently or sequentially in a patient, it is a major question whether they derive from the same lymphocyte or hematopoietic precursor cell or developed independently. We studied four composite classic Hodgkin lymphomas (HL) and other mature B-cell lymphomas, and two composite mature B- and T-cell neoplasias by whole exome sequencing (WES) and analyzed shared somatic mutations in the lymphomas of these clonally related composite lymphomas, indicating their derivation from a common, pre-malignant precursor. Most identified mutations were restricted to one or the other of these lymphomas, likely explaining how distinct lymphomas developed from a common ancestral B cell. In the two B-cell/T-cell lymphoma cases, and a composite clonally unrelated HL/chronic lymphocytic leukemia, the lymphoma partners did not share any somatic mutations. In three cases, we identified potentially oncogenic variants also in cells serving as constitutional controls.

  Study EGAS50000001017

• Exome sequencing in HIV+ Viremic Non-Progressors (VNPs) and HIV+ Progressors

  Viremic Non-Progressors (VNPs) maintain normal CD4+ T-cell counts despite uncontrolled HIV-1 replication, but mechanisms leading to CD4+ T-cell preservation are incompletely characterized. We aim to generate a comprehensive understanding of this infrequent phenotype by comparing rates of cellular infection, immunophenotype, genomics, single-cell transcriptomics, metabolomics, and levels of plasma biomarkers in 16 VNPs and 29 HIV+ Progressors. During chronic infection VNPs show lower frequency of HIV-1-infected cells in periphery, which is associated with reduced CCR5 expression and higher prevalence of CCR5Δ32 heterozygosity. The CD8+ T-cell compartment displays a less cytotoxic and less activated phenotype in VNPs. Moreover, despite similar viremia, we found lower bystander CD4+ T-cell death in the VNPs, together with weaker IFN responses, reduced plasma levels of zonulin (a biomarker of intestinal permeability), altered tryptophan catabolism, and preserved LPS responsiveness in vitro. Overall, a complex multifactorial mechanism, suggesting gut-associated lymphoid tissue preservation, underlies resistance to HIV pathogenesis in VNPs.

  Study EGAS50000000079

• Measles oncolytic virus as an immunotherapy for recurrent/refractory pediatric medulloblastoma and atypical teratoid rhabdoid tumor

  Pediatric recurrent medulloblastoma (MB) and atypical teratoid rhabdoid tumor (ATRT) are largely incurable and warrant novel therapies. We investigated a) the safety of a measles virus variant, MV-NIS, in a pediatric phase 1 study and b) the mechanisms of MV-NIS and potential benefit of combination with immune checkpoint inhibition (ICI). Pediatric patients with recurrent MB or ATRT were treated with intratumoral injections for local recurrence or via lumbar puncture for disseminated recurrence. We evaluated local immune responses to MV-NIS with and without ICI via single-cell and bulk RNA sequencing in an intracranial, immunocompetent, syngeneic murine model. MV-NIS given intratumorally or via repeat intrathecal dosing was safe. MV-NIS prolonged survival in murine models but did not demonstrate additive benefit with ICI. No changes in tumor-infiltrating immune-cell composition or activation were observed in response to MV-NIS treatment; however, MV-NIS induced local expression of neutralizing antibodies, complement cascade, and phagocytosis-related genes.

  Study EGAS50000000811

• 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

• Fragmentation signatures in cancer patients are similar to those in patients with vascular and autoimmune diseases

  The analysis of fragmentation patterns in plasma cell-free DNA (cfDNA) has been shown to distinguish individuals with cancer from healthy controls in multiple case-controlled studies. However, there have been few studies that investigate various types cfDNA fragmentomics patterns in individuals with other diseases. For this purpose, we developed a comprehensive metric, called fragmentation signatures, that integrated the distributions of fragment positioning, fragment length, and fragment end-motifs. Using this metric, we found that individuals with venous thromboembolism, systemic lupus erythematosus, dermatomyositis, or scleroderma had cfDNA fragmentation signatures that closely mimicked those found in individuals with advanced cancers. Furthermore, these signatures were highly correlated with increases in inflammatory markers in the blood. Though these data put substantial limitations on the specificity of fragmentomics-based tests for cancer diagnostics, they also offer ways to improve the interpretability of such tests. Moreover, they should lead to a better understanding of the cells – most likely inflammatory cells - from which plasma cfDNA is derived.

  Study EGAS00001008004

• 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

• Monosomy 7 delineates a primitive acute myeloid leukemia with adverse prognosis and responsiveness to epigenetic therapy

  The mechanistic basis for adverse risk associated with monosomy 7 remains undetermined in AML. In contrast to del(7q), monosomy 7 conferred adverse prognosis independent of TP53 and complex karyotype. Single-cell RNA and ATAC-seq revealed an epigenetically remodeled landscape and expansion of multipotent progenitor (MPP)-like cells. Monosomy 7 derived progenitors were distinguished by reduced chromatin accessibility and expression of STK17A and NT5C3A, which conferred resistance to cytotoxic and venetoclax-based therapy. To circumvent resistance mediated by monosomy 7 and deficient TP53, histone deacetylase inhibitors (HDACi) effectively restored apoptotic potential and augmented the activity of venetoclax. In a randomized clinical trial including older unfit patients with AML and monosomy 7, responses were observed in the majority that received low-dose cytarabine, venetoclax and the HDACi pracinostat, some with durable remissions exceeding 3 years. Longitudinal studies highlighted diminution of MPP-like cells, linking epigenetic remodeling to clinical response and therapeutic vulnerability of monosomy 7 AML.

  Study EGAS50000001641

• Kbtbd13 knock-down restores muscle function in a human-based mouse model of nemaline myopathy type 6

  Nemaline myopathy type 6 (NEM6) is caused by pathogenic variants in KBTBD13. Patients experience muscle weakness, excessive fatigue and impaired muscle relaxation which significantly impact their daily activities. NEM6 pathophysiology consist of abnormal protein aggregation in muscle cells and a predominance of slow-twitch myofibers, and most patients carry the Dutch founder variant in KBTBD13 (NP_001094832.1: p.Arg408Cys, referred to as KBTBD13R408C). Currently, no specific therapy is available. Here, we used a KBTBD13R408C knock-in mouse model and aimed to identify the molecular changes driving disease pathogenesis and to define a therapeutic window to test a therapeutic intervention. We revealed that the mouse model closely phenocopies the human phenotype at a morphological, functional, and transcriptional level and that the p.Arg408Cys variant causes mis-localization of KBTBD13 within the muscle sarcomere. Our natural history data in the Kbtbd13(R408C) mouse model showed that disease onset occurs between 1-3 months and plateaus by 9 months with little progression at 18 months.

  Study EGAS50000001678

• Full genome sequencing of a monozygotic twin discordant for schizophrenia

  We sequenced the genomes from a monozygotic twin discordant for schizophrenia and a tumor-normal pair of an ovarian cancer patient. Using whole-genome twin data to discriminate between correctly identified single nucleotide variants (SNVs) and errors a strategy for the accurate detection of SNVs was developed. By applying stringent sequencing quality measures, excluding error-prone regions and selecting SNVs identified by different mapping and variation calling algorithms, error rates were ~37-fold reduced. This enabled us to identify the first discordant SNVs in monozygotic twins using whole-genome sequencing. In addition, by showing that novel SNVs are highly enriched in errors, accurate estimates of the number of novel and rare SNVs occurring in unrelated Caucasian individuals were obtained. Finally, somatic mutations in coding and regulatory sequences were reliably identified in the highly rearranged ovarian tumor. Overall, our data demonstrate that strategies to reduce error rates in whole-genomes are required for disease gene discovery.

  Study EGAS00001000152

• Cancer genome scanning in plasma: detection of tumor-associated copy number aberrations, single nucleotide variants and tumoral heterogeneity by massively parallel sequencing

  Tumor-derived DNA can be found in the plasma of cancer patients. We explored the use of shotgun massively parallel sequencing of plasma DNA obtained from cancer patients to scan a cancer genome noninvasively. We achieved the profiling of copy number aberrations and point mutations, in a genomewide manner using this approach. By measuring the genomewide aggregated allelic loss and point mutations, we determined the fractional tumor-derived DNA concentrations in plasma and correlated these values with tumor size and surgical treatment. We have also demonstrated the application of this approach to monitoring a complex oncologic scenario, in a patient with two synchronous cancers. In particular, through the use of multi-regional sequencing of tumoral tissues and shotgun sequencing of plasma DNA, we have shown that plasma DNA sequencing is a valuable approach for studying tumoral heterogeneity. Shotgun plasma DNA sequencing is thus a powerful tool for cancer monitoring and research.

  Study EGAS00001000370

• GEenetic landscape of hypodiploid acute lymphoblastic leukemia

  Hypodiploid acute lymphoblastic leukemia (ALL) is an aggressive leukemia characterized by aneuploidy and poor outcome. The genetic basis of hypodiploid ALL is unknown. Here, using complementary genome-wide profiling approaches, we show that hypodiploid ALL comprises two subtypes that differ in the severity of aneuploidy, transcriptional profile and submicroscopic genetic alterations. Near haploid cases with 24-31 chromosomes frequently harbor alterations targeting receptor tyrosine kinase- and Ras signaling (71%) and IKZF3 (AIOLOS; 13%). In contrast, low hypodiploid ALL cases with 32-39 chromosomes are characterized by TP53 alterations, almost half of which are present in non-tumor cells, and have alterations of IKZF2 (HELIOS; 53%) and RB1 (41%). Both near haploid and low hypodiploid tumors exhibit activation of Ras and PI3K signaling pathways, and are sensitive to PI3K inhibition, indicating that these drugs should be explored as a new therapeutic strategy for this frequently lethal form of leukemia.

  Study EGAS00001000380

• EuCANCan: EUropean-CANadian Cancer network

  The EUropean-CANadian Cancer network (EuCANCan) is a project aiming to develop a federated network of aligned and interoperable infrastructures for the homogeneous analysis, management and sharing of genomic oncology data for Personalized Medicine. This initiative, funded by the European Commission and the Canadian Institutes of Health and coordinated by the Barcelona Supercomputing Center (BSC), is expected to process and provide the scientific community with around 30-35 thousand patient samples from different types of cancer, coming from different nodes involved in this project, during the four years of the project. Data generated as part of primary studies, often in small hospitals or research centers, is hardly reused by other projects or groups. EuCANCan is proposed to foster the homogenisation and discoverability of cancer samples from very different sources for the whole community. These efforts will help paving the way to future standardised and global genomics projects, specially for those participant countries that eventually integrate the methodology and infrastructure generated during the project. “The more data we have access to the more and better discoveries. We attempt to overcome the legal and technical limitations in order to generate, gather and exploit bigger datasets as well as answer more ambitious questions”. These were some of the words Dr. David Torrents, main coordinator of the project, shared with a regional radio during the kick-off meeting of the project, on February 11th, 2019. The EUCANCan network will be composed of reference nodes in Amsterdam, Barcelona, Berlin, Heidelberg, Paris and Toronto which have established strong research and clinical programs in the field of genomic oncology. The Centre for Genomic Regulation (CRG), specifically the European Genome-phenome Archive (EGA), is among the leading institutions. Its exhaustive experience in biomedical data archival and secure distribution is considered key for crucial developments within the project. It is also notable the recent inclusion of EUCANCan in the list of GA4GH driver projects. Further information and details can be found in the following links: InsideHPC BSC official description Techweek (Spanish)

  Blog eucancan

• Somatic mutations in ALS genes in the motor cortex of sporadic ALS patients

  Several lines of evidence suggest that amyotrophic lateral sclerosis (ALS) pathology starts focally and spreads within the central nervous system (CNS). We leveraged DNA and RNA sequencing data from ALS autopsy tissue to explore the presence of somatic mosaic variants in sporadic ALS (sALS) cases. Deep targeted sequencing of known ALS disease genes from motor cortex tissue revealed enrichment of somatic variants in sALS compared to familial ALS (fALS) with a monogenic cause and an increased pathogenicity of mosaic mutations in known ALS mutational hot spots. Experimental validation of the variants identified that the somatic FUS variant p.E516X leads to nucleo-cytoplasmic mislocalization and aggregation. Additionally, somatic variant calling from single-cell RNA-sequencing data of sALS tissue showed an accumulation of somatic variants in excitatory neurons. Collectively, using a multi-modal approach, our findings suggest that somatic mutations within the motor cortex, especially in excitatory neurons, may contribute to the development of sALS.

  Study EGAS00001008104

• The genomic landscape of relapsed infant and childhood KMT2A-rearranged acute leukemia

  To study the mechanisms of relapse in KMT2A-rearranged (KMT2A-r) acute lymphoblastic (ALL) and acute myeloid leukemia (AML), we performed whole-genome and exome sequencing of infants and children with relapsed ALL/AML (n=36), and longitudinal deep-sequencing of 257 samples in 30 patients. Somatic alterations in drug-response genes, most commonly in TP53 and IKZF1 (64%), were highly enriched in early relapse ALL (79%, 9-36 months after diagnosis), but rare in very early relapse ALL (<9 months, 9%). A marked chemotherapy-exposure signature was detected for mutations in early relapse ALL but not in very early ALL or AML relapse, in line with different mechanisms of relapse. Longitudinal analyses could track residual leukemia cells, clonal drug responses, and the upcoming relapse. These results highlight that KMT2A-r ALL and AML evade therapy differently and provide new insights into the mechanisms of relapse in this highly lethal form of pediatric acute leukemia.

  Study EGAS00001008197

• EATL-II STUDY

  Enteropathy-associated T-cell lymphoma (EATL), a rare and aggressive intestinal malignancy of intraepithelial T lymphocytes, comprises two disease variants (EATL-I and EATL-II) differing in clinical characteristics and pathological features. Here we report findings derived from whole exome sequencing of 15 EATL-II tumor-normal tissue pairs. The tumor suppressor gene SETD2 encoding a non-redundant H3K36-specific trimethyltransferase is altered in 14/15 cases (93%), mainly by loss-of-function mutations and/or loss of the corresponding locus (3p21.31). These alterations consistently correlate with defective H3K36 trimethylation. The JAK/STAT pathway comprises recurrent STAT5B (60%), JAK3 (46%) and SH2B3 (20%) mutations, including a STAT5B V712E activating variant. Additionally, frequent mutations in TP53, BRAF and KRAS are observed. Conversely, in EATL-I, no SETD2, STAT5B or JAK3 mutations are found, and H3K36 trimethylation is preserved. This study describes SETD2 inactivation as EATL-II molecular hallmark, supports EATL-I and -II being two distinct entities, and defines potential new targets for therapeutic intervention.

  Study EGAS00001001879

• 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

• Transcriptional and functional profiling defines human small intestinal macrophage subsets

  Macrophages (Mf) are instrumental in maintaining immune homeostasis in the intestine, yet studies on origin and heterogeneity of human intestinal Mf are scarce. Here, we identified four distinct Mf subpopulations in human small intestine (SI). Assessment of their turnover in duodenal transplants revealed that all Mf subsets were completely replaced over time; Mf1 and Mf2, phenotypically similar to peripheral blood monocytes (PBMo), were largely replaced within 3 weeks, whereas two subsets with features of mature Mf, Mf3 and Mf4, exhibited significantly slower replacement. Mf3 and Mf4 localized differently in SI; Mf3 formed a dense network in mucosal lamina propria, whereas Mf4 was enriched in submucosa. Transcriptomic analysis showed that all Mf subpopulations subsets were markedly distinct from PBMo and dendritic cells (DC). Compared to PBMo, Mf subpopulations showed reduced responsiveness to proinflammatory stimuli, but were proficient at endocytosis of particulate and soluble material. These data provide a comprehensive analysis of human SI Mf population and suggest a precursor-progeny relationship with PBMo.

  Study EGAS00001002093

• Whole genome sequencing data for 10 hepatocellular carcinomas (HCC) and matched non-tumor liver tissues + optical mapping data for 4 HCC and 3 matched non-tumor liver tissues.

  Oncogene activation leads to replication stress and promotes genomic instability. Here we combine optical mapping and whole genome sequencing to explore in-depth the nature of structural variants (SVs) induced by replication stress in cyclin-activated hepatocellular carcinomas (CCN-HCC). In addition to classical tandem duplications, CCN-HCC display frequent intra- and inter-chromosomal templated insertion cycles (TIC) likely resulting from template switching events. Template switching preferentially involves active topologically associated domains that are close in the 3D genome organization. Template sizes depend on the type of cyclin activation and are coordinated within each TIC. Replication stress induces continuous accumulation of SVs during CCN-HCC progression, fostering the acquisition of new driver alterations and large-scale copy-number changes at TIC borders. Together, this analysis sheds light on the mechanisms, dynamics and consequences of SV accumulation in tumors with oncogene-induced replication stress.

  Study EGAS00001005629

• Resequencing_candidate_genes_for_male_spermatogenic_impairment

  This study aims to identify novel candidate variants from human Y-chromosomal genes DAZ, BPY2 and CDY1 by resequencing the coding regions of these genes from male patients with spermatogenic impairment. The coding regions of the genes have been amplified by standard PCR, amplicon lengths range from 244 to 486 bp. A total of 61 amplicons were amplified for each of the 96 patients, totalling to approx. 25 kb per sample. Amplicons were quantified by gel electrophoresis and pooled in approx. equimolar concentrations per patient. For each of the 96 submitted samples, approx. 1 microgram of amplified DNA pool is provided in a total volume of 120 microlitres. The samples need to be indexed and libraries prepared for a PE250bp Illumina MiSeq run. This data is part of a pre-publication release. For information on the proper use of pre-publication data shared by the Wellcome Trust Sanger Institute (including details of any publication moratoria), please see http://www.sanger.ac.uk/datasharing/

  Study EGAS00001002157

• Genetic Basis of Hepatosplenic T Cell Lymphoma (HSTL)

  Hepatosplenic T cell lymphoma (HSTL) is a rare and lethal lymphoma; the genetic drivers of this disease are unknown.  Through whole exome sequencing of 68 HSTLs, we define recurrently mutated driver genes and copy number alterations in the disease. Chromatin modifying genes including SETD2, INO80 and ARID1B were commonly mutated in HSTL, affecting 62% of cases. HSTLs manifest frequent mutations in STAT5B (31%), STAT3 (9%), and PIK3CD (9%) for which there currently exist potential targeted therapies. In addition, we noted less frequent events in EZH2, KRAS and TP53. SETD2 was the most frequently silenced gene in HSTL. We experimentally demonstrated that SETD2 acts as a tumor suppressor gene. In addition, we found that mutations in STAT5B and PIK3CD activate critical signaling pathways important to cell survival in HSTL. Our work thus defines the genetic landscape of HSTL and implicates novel gene mutations linked to HSTL pathogenesis and potential treatment targets.

  Study EGAS00001002182

• miR-200-regulated CXCL12β promotes fibroblast heterogeneity and immunosuppression in ovarian cancers

  High-grade serous epithelial ovarian cancer (HGSOC) has been recently subdivided into molecular subgroups, including the mesenchymal HGSOC associated with partial tumor-debulking surgery and poor patient survival. Consistent with stromal-related genes signatures defining mesenchymal HGSOC, we show here that stroma plays a key function in this HGSOC molecular subtype. We first highlight stromal heterogeneity in HGSOC by identifying 4 subsets of Carcinoma-Associated Fibroblast (CAF-S1-4). Mesenchymal HGSOC significantly accumulate the activated CAF-S1 subset, which exhibits immunosuppressive functions by promoting attraction, survival and activation of regulatory T-lymphocytes. The CXCL12β chemokine reliably characterizes mesenchymal HGSOC and specifically accumulates in the CAF-S1 subset through a regulation mediated by the miR-141/200a. CXCL12β promotes attraction of T-lymphocytes and is thus a key actor in CAF-S1-mediated immunosuppressive functions. In conclusion, we highlight here for the first time stromal heterogeneity and immunosuppression in mesenchymal HGSOC that could participate in the poor patient prognosis.

  Study EGAS00001002184

• DONSON encodes a novel replication fork protection factor mutated in microcephalic dwarfism.

  To ensure efficient genome duplication, cells have evolved a multitude of factors that promote unperturbed DNA replication, and protect, repair and restart damaged forks. Here we identify DONSON as a novel fork protection factor, and report biallelic DONSON mutations in 29 individuals with microcephalic dwarfism. We demonstrate that DONSON is a component of the replisome that stabilises forks during normal genome replication. Loss of DONSON leads to severe replication-associated DNA damage arising from nucleolytic cleavage of stalled replication forks. Furthermore, ATR-dependent signalling in response to replication stress is impaired in DONSON-deficient cells, resulting in decreased checkpoint activity, and potentiating chromosomal instability. Hypomorphic mutations substantially reduce DONSON protein levels and impair fork stability in patient cells, consistent with defective DNA replication underlying the disease phenotype. In summary, we identify mutations in DONSON as a common cause of microcephalic dwarfism, and establish DONSON as a critical replication fork protein required for mammalian DNA replication and genome stability.

  Study EGAS00001002224

• Whole-Genome Sequencing of a Healthy Aging Cohort.

  Studies of long-lived individuals have revealed few genetic mechanisms for protection against age-associated disease. Therefore, we pursued genome sequencing of a related phenotype-healthy aging-to understand the genetics of disease-free aging without medical intervention. In contrast with studies of exceptional longevity, usually focused on centenarians, healthy aging is not associated with known longevity variants, but is associated with reduced genetic susceptibility to Alzheimer and coronary artery disease. Additionally, healthy aging is not associated with a decreased rate of rare pathogenic variants, potentially indicating the presence of disease-resistance factors. In keeping with this possibility, we identify suggestive common and rare variant genetic associations implying that protection against cognitive decline is a genetic component of healthy aging. These findings, based on a relatively small cohort, require independent replication. Overall, our results suggest healthy aging is an overlapping but distinct phenotype from exceptional longevity that may be enriched with disease-protective genetic factors.

  Study EGAS00001002306

• Molecular Subtype-specific Biomarkers Improves Colorectal Cancer Prognostication

  Colorectal cancer (CRC) is characterized by major inter-tumor diversity that complicates the prediction of disease and treatment outcomes. Recent efforts help resolve this by sub-classification of CRC according to natural molecular subtypes, however, this strategy is not yet able to provide clinicians with improved tools for decision-making. We here present an extended framework for CRC stratification that specifically aims to improve patient prognostication. Using transcriptional profiles from 1,100 CRCs, including a novel set of >300 samples, we identify novel cancer cell and tumor archetypes and suggest the tumor microenvironment as a major prognostic determinant that can be influenced by the microbiome. Notably, our subtyping strategy allowed identification of novel archetype-specific prognostic biomarkers that provided information beyond and independent of UICC-TNM staging, MSI-status and consensus molecular subtyping. The results illustrate that our extended subtyping framework, combining subtyping and subtype-specific biomarkers, could contribute to improved patient prognostication and may form a strong basis for future studies.

  Study EGAS00001002376