Search Results - EGA European Genome-Phenome Archive

CD8-targeted IL-2 unleashes tumor-specific immunity in human cancer tissue by reviving the dysfunctional T cell pool

Tumor-specific CD8+ T cells are key effectors of antitumor immunity but are often rendered dysfunctional in the tumor microenvironment. Immune checkpoint blockade can restore antitumor T cell function in some patients, however most do not respond to this therapy, often despite T cell infiltration in their tumors. We here explored a CD8-targeted IL-2 fusion molecule (CD8-IL2) to selectively reactivate intratumoral CD8+ T cells in patient-derived tumor fragments. Treatment with CD8-IL2 broadly armed intratumoral CD8+ T cells with enhanced effector capacity, thereby specifically enabling reinvigoration of the dysfunctional T cell pool to elicit potent immune activity. Notably, the revival of dysfunctional T cells to mediate effector activity by CD8-IL2 depended on simultaneous antigen recognition and was quantitatively and qualitatively superior to that achieved by PD-1 blockade. Finally, CD8-IL2 was able to functionally reinvigorate T cells in tumors resistant to anti-PD-1, underscoring its potential as a novel treatment strategy for cancer patients.

Study EGAS00001007712

ScRNA-seq of human kidney immune cells of patients with ANCA-associated glomerulonephritis, Lupus Nephritis against a "healthy" nephrectomy control

ANCA-associated glomerulonephritis (AGN) associates with a high risk of end-stage kidney disease. The role of kidney immune cells in local inflammation remains unclear. Here, we investigate kidney immune cell diversity and function. Kidney tissue from AGN patients (n=5) and a lupus nephritis (LN) patient (n=1) were aquired during a biopsy procedure for a clinical indication. Needle-core biopsies were obtained for histopathological examination, and an additional pass was performed to retrieve kidney tissue for scRNA-seq. Healthy kidney tissue (n=1) was obtained from a kidney that was surgically removed do tue due to a (non-invasive) papillary urothelial carcinoma. Immediately after collection, kidney tissue was processed into a single-cell suspension and sorted using a 4-color flow cytometry panel to isolate living, CD45+ immune cells. To aid in the multi-omic characterization, surface markers and T and B cell repertoires were sequenced in 2 samples (1 AGN patient and the nephrectomy control). These samples were incubated with an oligo-antibody TotalSeq-C cocktail containing 130 unique cell surface antigens.

Study EGAS50000000159

WES in HCCOs with varying Doxorubicin resistance

We aimed to identify somatic mutations that could explain the resistance to Doxorubicin. Therefor, we purified Exomes from liver biopsies and HCC organoids using Agilent SureSelectXT (clinical research exome, HS2 V8, or Human all Exon V6 Cosmic) and performed WES. Matched non-tumoral liver biopsies served as the control for germline mutations. 12 of these samples were previously reported. Sequence reads were aligned to the reference human genome GRCh38 using Burrows-Wheeler Aligner (BWA, v0.7.17). Duplicate removal, base quality adjustment, mutation calling (Mutect2, intervals: SureSelectXT_HS_V8_S33266340, germline-recourse: gnomad.exomes.r2.1.1.sites.liftover_grch38, Panel-of-Normal: 1000g_pon.hg38), filtering of Mutect calls, and functional annotation (Funcotator, funcotator_dataSources.v1.7.20200521g) were performed using the Genome Analysis Toolkit (GATK, v4.4) according to the Broad Institute best practices in Somatic short variant discovery workflows. Mutations with a functional annotation of Deletion, Insertion, Non-stop, Splice-Site, Start-Codon and Missense mutations were kept. A list of 43 commonly mutated genes in HCC was analyzed in the HCC organoids [TCGA, Comprehensive and Integrative Genomic Characterization of Hepatocellular Carcinoma. Cell, 2017. 169(7): p. 1327-1341.e23].

Study EGAS50000000043

Genetic_mechanisms_of_resistance_to_chemotherapy_in_breast_cancer

Resistance towards chemotherapy is one of the main causes of treatment failure and deathamong breast cancer patients.The main objective of this project is to identify genetic mechanisms causing some breastcancer patients not to respond to a particluar type of chemotherapy (epirubicin) while otherpatients respond very well to the same treatment.In the project we will perform genome / exome sequencing of a selection of breast cancerpatients (n=30). These patients are drawn from a cohort where all patients have recievedtreatment with epirubicin monotherapy before surgical removal of a locally advanced breasttumour, and where all patients have been subjected to objective evaluation of the response tothe therapy.Subsequent to sequencing, we will analyse the data and compare with the clinical data foreach patient (object response to therapy). The main aim being to identify mutations that areassociated with resistance to epirubicin.Identification of mutations with strong predictive value, may have a direct impact on cancertreatment since it opens the possibility for genetic testing of a tumour, and desicion on whichdrug is likely to work best, prior to treatment start.

Study EGAS00001000276

Integrative genomic profiling of large-cell neuroendocrine carcinomas reveals distinct subtypes of high-grade neuroendocrine lung tumors

Large-cell neuroendocrine lung carcinomas (LCNEC) have similarities with other lung cancers, but their precise relationship has remained unclear. We conducted comprehensive genomic (n=60) and transcriptomic (n=69) analyses of 75 LCNECs and identified two molecular subgroups: “type I LCNECs” with bi-allelic TP53 and STK11/KEAP1 alterations (37%), and “type II LCNECs” enriched for bi-allelic inactivation of TP53 and RB1 (42%). Despite sharing genomic alterations with adenocarcinomas and squamous cell carcinomas, no transcriptional relationship was found; instead LCNECs form distinct transcriptional subgroups with closest similarity to SCLC. While type I LCNECs and SCLCs exhibit a neuroendocrine profile with ASCL1high/DLL3high/NOTCHlow, type II LCNECs bear TP53 and RB1 alterations and differ from most SCLC tumors with reduced neuroendocrine markers, a pattern of ASCL1low/DLL3low/NOTCHhigh and upregulation of immune-related pathways. In conclusion, LCNECs are comprised of two molecularly defined subgroups, and distinguishing them from SCLC may allow for stratified targeted treatments for high-grade neuroendocrine lung tumors.

Study EGAS00001000708

Transcriptomics sequencing analysis of pre-invasive lung adenocarcinoma in never-smokers

The prevalence of lung adenocarcinoma (LUAD) has increased sharply in East Asia. Early diagnosis leads to better survival rates, but this requires an improved understanding of the molecular changes during early tumorigenesis, particularly in non-smokers. We performed whole exome-sequencing and RNA-sequencing for samples from 94 East Asian patients with precancerous lesions (25 with atypical adenomatous hyperplasia [AAH]; 69 with adenocarcinoma in situ [AIS]) and 73 patients with early invasive lesions (minimally invasive adenocarcinoma [MIA]). Cellular analysis revealed that the activities of endothelial and stromal cells could categorize tumors into molecular subtypes within pathology-defined lesion types. These subtypes were linked with the advanced radiology-defined lesion type and coordinated with immune cell infiltration throughout the progression of LUAD. Characterization of these lesion types identified positively selected mutation patterns, and suggested that angiogenesis of the late-stage AIS type potentially contributes to tissue invasion of the MIA type. Our findings offer a novel resource that may help to improve early diagnosis and patient prognosis, and also suggest possible approaches for early disease interception.

Study EGAS50000000439

Copy number variations and fragmentation features in cell-free DNA predict response in advanced non-small cell lung cancer patients under anti-PD-(L)1 therapy

Anti-PD-(L)1 therapy is routinely used in metastatic NSCLC. However, response rates vary and biomarkers predicting treatment efficacy are lacking. Liquid biopsies allow monitoring of residual disease during therapy. Residual circulating tumor DNA (ctDNA) after therapy represents a predictive marker for adverse outcome. Here, we assessed copy number variations (CNVs) in serial plasma samples of NSCLC patients receiving PD-(L)1 blockade. We profiled CNV and fragmentation features in 118 plasma samples of advanced NSCLC patients by low-coverage whole genome sequencing taken at baseline, after four therapy cycles and at disease progression. CNVs and fragment features (i.e., fragment length, end motifs, position) were significantly altered in patients compared to healthy donors. Furthermore, fragment length changes at baseline and residual CNVs after four therapy cycles correlated with short progression-free survival. Our results highlight the suitability of plasma-based CNV and fragment analysis for disease monitoring and as a predictive marker for response duration in NSCLC patients under anti-PD-(L)1 therapy.

Study EGAS50000000441

RNA Editing in breast cancer

High-throughput sequencing screens suggest that RNA editing, which consists in the substitution of adenosine with inosine by the RNA-specific adenosine deaminase (ADAR) enzyme, occurs at several thousand positions across the human genome. Recent evidences have shown that RNA-editing could promote proliferation and carcinogenesis; however, the general principles of ADAR activity on the transcriptome and how ADAR is controlled in cancers remain to be established. The main aim of this project was to investigate the phenomenon of RNA editing in breast and other cancers. The frequency of A-to-I editing was evaluated in 58 breast cancers equally distributed among the different molecular subtypes and 10 normal breast tissues. The analysis was focused on defining: the relationship between the global amount of editing and ADAR expression; the ability to predict the level of editability of specific sites; the distribution of editing in normal and tumour samples and among different breast cancer subtypes; and the clinical, pathological and genomic factors affecting editing.

Study EGAS00001000495

Analysis of translatome, truncating mutations, lncRNA, circRNA and microproteins of 80 human DCM cases and controls

The regulation of gene expression in healthy and diseased human tissues is incompletely understood and has primarily been studied on the transcriptional level. Here, we quantify the impact of translation on gene expression and annotate novel translational events in 80 human hearts. These include 65 tissues from patients with dilated cardiomyopathy (DCM) - the most common cause of heart transplantation – and 15 unaffected controls. We show that translational regulation modulates disease-associated molecular processes. Further, we evaluate ribosome dynamics at protein truncating variants revealing incomplete termination of translation at titin-truncating variants (TTNtv) that commonly cause DCM. Finally, we identify dozens of unknown microproteins translated from lncRNAs and circRNAs and link these to mitochondrial processes. Several microproteins are expressed from lncRNAs with previously demonstrated function, suggesting a dual coding and noncoding role. This resource will stimulate novel functional investigations into cardiac biology in health and disease and may serve as a blueprint for characterizing the translational landscape of other human tissues.

Study EGAS00001003263

Whole exome sequencing of pre-invasive lung adenocarcinoma in non-smokers

The prevalence of lung adenocarcinoma (LUAD) has increased sharply in East Asia. Early diagnosis leads to better survival rates, but this requires an improved understanding of the molecular changes during early tumorigenesis, particularly in non-smokers. We performed whole exome-sequencing and RNA-sequencing for samples from 94 East Asian patients with precancerous lesions (25 with atypical adenomatous hyperplasia [AAH]; 69 with adenocarcinoma in situ [AIS]) and 73 patients with early invasive lesions (minimally invasive adenocarcinoma [MIA]). Cellular analysis revealed that the activities of endothelial and stromal cells could categorize tumors into molecular subtypes within pathology-defined lesion types. These subtypes were linked with the advanced radiology-defined lesion type and coordinated with immune cell infiltration throughout the progression of LUAD. Characterization of these lesion types identified positively selected mutation patterns, and suggested that angiogenesis of the late-stage AIS type potentially contributes to tissue invasion of the MIA type. Our findings offer a novel resource that may help to improve early diagnosis and patient prognosis, and also suggest possible approaches for early disease interception.

Study EGAS50000000438

Cancer cell and tumor microenvironment biomarkers associated with disease-free survival with adjuvant nivolumab in the phase 3 CheckMate 274 trial

In the CheckMate 274 trial, adjuvant nivolumab versus placebo demonstrated an improvement in the primary endpoint of disease-free survival (DFS) in patients with high-risk muscle-invasive urothelial carcinoma after radical resection. An extensive analysis of tumor biomarkers, including their associations with DFS, was performed. Analysis of genome-wide differential gene expression and known gene signatures found that immune-related genes and pathways, in particular an IFNγ signature, were predictive of DFS in nivolumab-treated patients. Predictive and prognostic associations, respectively, were found for tumor-infiltrating CD4 and CD8 T cells. Analysis of a composite predictive model suggested that CD4 gene expression and tumor cell PD-L1 expression had the greatest contributions to predicting outcomes in nivolumab-treated patients. These results reinforce recent studies establishing the importance of biomarkers of adaptive immunity, and in particular CD4 T cells, in influencing response to PD-1/PD-L1 blockade and establish the potential predictive rather than solely prognostic nature of such findings.

Study EGAS50000000560

ALPI deficiency causes refractory Inflammation Bowel Disease

Herein, we report the first identification of biallelic-inherited mutations in ALPI as a Mendelian cause of inflammatory bowel disease in two unrelated patients. ALPI encodes for intestinal phosphatase alkaline, a brush border metalloenzyme that hydrolyses phosphate from the lipid A moiety of lipopolysaccharides and thereby drastically reduces Toll-like receptor 4 agonist activity. Prediction tools and structural modelling indicate that all mutations affect critical residues or inter-subunit interactions, and heterologous expression in HEK293T cells demonstrated that all ALPI mutations were loss of function. ALPI mutations impaired either stability or catalytic activity of ALPI and rendered it unable to detoxify lipopolysaccharide-dependent signalling. Furthermore, ALPI expression was reduced in patients' biopsies, and ALPI activity was undetectable in ALPI-deficient patient's stool. Our findings highlight the crucial role of ALPI in regulating host-microbiota interactions and restraining host inflammatory responses. These results indicate that ALPI mutations should be included in screening for monogenic causes of inflammatory bowel diseases and lay the groundwork for ALPI-based treatments in intestinal inflammatory disorders.

Study EGAS00001003350

IL-27 promotes tumour control by enhancing cytotoxic T cell function

Cytotoxic CD8+ T lymphocytes (CTL) are essential for anti-tumour immunity but are frequently dysfunctional in established tumours. Here, we show that expression of a CTL signature is strongly associated with IL-27 expression in diverse human and murine tumours. In mice, IL-27 acts directly on tumour-specific CTL to promote their persistence and effector function in the tumor microenvironment. Moreover, treatment with inducible IL-27 overexpression or a half-life-extended IL-27 protein in vivo is well tolerated, induces regression of large established tumours, drives an enhanced cytotoxic program in anti-tumour CTL, and synergizes with PD-L1 blockade. In cancer patients treated with anti-PD-1 or anti-PD-L1 therapy, high expression of IL-27 is associated with improved clinical response. Finally, IL-27 increases cytotoxicity and limits terminal differentiation of human CD8+ T cells during chronic antigen exposure. Our data demonstrate that endogenous IL-27 is essential for anti-tumour immunity and that IL-27 receptor agonism can safely improve anti-tumor T cell responses alone or in combination with PD-L1 blockade.

Study EGAS50000000694

Anti-myeloperoxidase IgM B cells in anti-neutrophil cytoplasmic antibody-associated vasculitis

Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a prototypic autoimmune disease, with a subset of AAV patients manifesting anti-myeloperoxidase (MPO) IgG. Patients with AAV respond positively to B cell-targeting and complement-targeting therapies, but disease flares are not uncommon. Here, by comparing samples from healthy individuals and MPO+ AVV patients, we show that B cell autoreactivity against MPO in the circulation of patients is dominated by CD27+IgM+ B cells whereas MPO-specific IgG+ cells are infrequent. Additionally, while naive anti-MPO-IgM B cells are present in both patients and controls and produce anti-MPO IgM upon stimulation, anti-MPO-IgM memory B cells and serum anti-MPO IgM are features of patients. Our results thus hint that defective elimination of B cell reactivity to MPO in the human repertoire, the presence of activated IgM+ anti-MPO B cells in disease, and a dominant role for anti-MPO IgM in complement activation, may all contribute to MPO+ AAV etiology and thereby serve as potential target for therapy.

Study EGAS50000000753

Development of a fully human glioblastoma-in-brain-spheroid model for accelerated translational research

In glioblastoma (GBM) the intricate interplay between tumor cells and the surrounding microenvironment plays a crucial role in tumor progression, invasion, and therapeutic resistance. So far, studying these interactions in a controlled and representative model system has been challenging. Here, we report the development of hGliCS, a human glioma-cortical spheroid model that allows the elucidation of the biology of GBM cells and their interactions with a human-specific brain-like microenvironment and neurons. GBM cells efficiently invade the cortical spheroids, forming a well-connected network of communicating cells. The heterogeneous cellular states of the GBM cells within this model closely resembled findings previously observed in glioblastoma patients and in mouse xenografts. We observed a transition from predominantly mesenchymal-like cells to heterotopic states with a high diversity. In contrast to the substantial changes observed in the tumor cell population, the impact of the GBM cells on the neurons was minimal. We further demonstrate the suitability of hGliCS to test compounds targeting tumor-specific neurobiological features.

Study EGAS50000000757

Blood-based monitoring of relapsed/refractory cHL patients predict responses to PD-1 blockade treatment

Hodgkin lymphoma (cHL) patients are uniquely susceptible to treatment with programmed cell death-1 (PD-1) treatment. However, monitoring with FDG-PET/CT, the current response detection standard, is challenging. Here, we address the potential applicability of tissue biomarkers and blood-based biomarkers in PD-1 treated cHL patients. We evaluated 9p24.1/PD-L1/PD-L2 alterations, and expression of PD-L1 and antigen presentation molecules (HLA class I/II) in 9 tissue biopsies of 4 patients. In addition, we assessed circulating tumor DNA (ctDNA), extracellular vesicle associated miRNAs (EV-miRNAs), soluble PD-L1 and serum TARC (sTARC) in 26 longitudinal blood samples of these patients during PD-1 treatment. We found that the predictive power of tissue biomarkers is dependent on the timing of the biopsy . The dynamics of blood-based biomarkers: sTARC, EV-miRNAs and ctDNA corresponded well immunotherapy treatment response. Therefore, blood-based biomarkers are promising monitoring strategies in PD-1 treated cHL patients and should be further explored in clinical trials or observational studies.

Study EGAS00001005894

Assessment of candidate high-grade serous ovarian carcinoma predisposition genes through integrated germline and tumour sequencing

High-grade serous ovarian carcinoma (HGSOC) has a significant hereditary component, only half of which is explained. Previously, we performed germline exome sequencing on BRCA1 and BRCA2-negative HGSOC patients, revealing three proposed and 43 novel candidate genes enriched with rare loss-of-function variants. For validation, we undertook case-control analyses using genomic data from disease-free controls. This confirms enrichment for nearly all previously identified genes. Additionally, one-hundred-and-eleven HGSOC tumours from variant carriers were sequenced alongside other complementary studies, seeking evidence of biallelic inactivation as supportive evidence. PALB2 and ATM validate as HGSOC predisposition genes, with 6/8 germline carrier tumours exhibiting biallelic inactivation accompanied by characteristic mutational signatures. Among candidate genes, only LLGL2 consistently shows biallelic inactivation and protein expression loss, supporting it as a novel HGSOC susceptibility gene. The remaining candidate genes fail to validate. Integrating case-control analyses with tumour sequencing is thus crucial for accurate gene discovery in familial cancer studies.

Study EGAS50000000770

Dissecting intratumor heterogeneity of nodal B cell lymphoma on the transcriptional, genetic, and drug response level

Tumor heterogeneity encompasses both the malignant cells and their microenvironment. While heterogeneity between individual patients is well-known to affect the efficacy of anti-cancer, most personalized treatment approaches do not account for intratumor heterogeneity. We addressed this issue by studying the heterogeneity of lymph node-derived B cell non-Hodgkin lymphoma (B-NHL) by single cell RNA-sequencing (scRNA-seq) and transcriptome-informed flow cytometry. We identified transcriptionally distinct malignant subclones and compared their drug response and genomic profiles. Malignant subclones of the same patient responded strikingly different to anti-cancer drugs ex vivo, which recapitulated subclone-specific drug sensitivity during in vivo treatment. Tumor infiltrating T cells represented the majority of non-malignant cells, whose gene expression signatures were similar across all donors, whereas the frequencies of T cell subsets varied significantly between the donors. Our data provide new insights into the heterogeneity of B-NHL and highlight the relevance of intratumor heterogeneity for personalized cancer therapies.

Study EGAS00001004335

Molecular subsets in renal cancer determine outcome to checkpoint and angiogenesis blockade

We conducted integrated multi-omics evaluation of 823 tumors from advanced renal cell carcinoma (RCC) patients and identified molecular subsets associated with differential clinical outcomes to angiogenesis blockade alone or with a checkpoint inhibitor. Unsupervised transcriptomic analysis revealed six molecular subsets with distinct angiogenesis, immune, cell cycle, metabolism, and stromal programs. While sunitinib was effective in subsets with high angiogenesis, atezolizumab+bevacizumab improved clinical benefit in tumors with high T-effector and/or cell cycle transcription. Somatic mutations in PBRM1 and KDM5C associated with high angiogenesis and AMPK/Fatty acid oxidation gene expression, while CDKN2A/B and TP53 alterations were more prevalent in tumors with increased cell cycle and anabolic metabolism. Sarcomatoid tumors exhibited low prevalence of PBRM1 mutations and angiogenesis markers, frequent CDKN2A/B, BAP1 and TP53 alterations, and increased PD-L1 expression. These findings can be applied to molecularly stratify advanced RCC patients, explain improved outcomes of sarcomatoid tumors to checkpoint blockade, and develop personalized therapies.

Study EGAS00001004353

Genome-wide prediction of human embryos

BACKGROUND: Preimplantation genetic diagnosis (PGD) enables profiling of embryos for genetic disorders prior to implantation. The majority of PGD testing is restricted in the scope of variants assayed or by the availability of extended family members. While recent advances in single cell sequencing show promise, they remain limited by bias in DNA amplification and the rapid turnaround time (<36 h) required for fresh embryo transfer. Here, we describe and validate a method for inferring the inherited whole genome sequence of an embryo for preimplantation genetic diagnosis (PGD). METHODS: We combine haplotype-resolved, parental genome sequencing with rapid embryo genotyping to predict the whole genome sequence of a day-5 human embryo in a couple at risk of transmitting alpha-thalassemia. RESULTS: Inheritance was predicted at approximately 3 million paternally and/or maternally heterozygous sites with greater than 99% accuracy. Furthermore, we successfully phase and predict the transmission of an HBA1/HBA2 deletion from each parent. CONCLUSIONS: Our results suggest that preimplantation whole genome prediction may facilitate the comprehensive diagnosis of diseases with a known genetic basis in embryos.

Study EGAS00001001020

Combined hereditary and somatic mutations of replication error repair genes result in rapid onset of ultra-hypermutated cancers

DNA replication-associated mutations are repaired by two components: polymerase proofreading and mismatch repair. The mutational consequences of disruption to both repair components in humans are not well studied. We sequenced cancer genomes from children with inherited biallelic mismatch repair deficiency (bMMRD). High-grade bMMRD brain tumors exhibited massive numbers of substitution mutations (>250/Mb) – higher than all childhood and most cancers (>7000 analyzed). All ultra-hypermutated bMMRD cancers acquired early somatic driver mutations in DNA polymerases epsilon or delta. The ensuing mutation signatures and numbers are unique and diagnostic of childhood germline bMMRD (p<10e-13). Sequential tumor biopsy analysis revealed that bMMRD/polymerase mutant cancers rapidly amass an excess of simultaneous mutations (~600 mutations/cell division), reaching but not exceeding ~20,000 exonic mutations in <6 months. Thus implying a threshold compatible with cancer cell survival. We suggest a new mechanism of cancer progression in which mutations develop in a rapid burst after ablation of replication repair.

Study EGAS00001001112

MINCR is a MYC-induced lncRNA able to modulate MYC’s transcriptional network in Burkitt lymphoma cells

Despite the established role of the transcription factor MYC in cancer, little is known about the involvement of lncRNAs in mediating MYC’s function. Here we have intersected RNA-sequencing data from MYC-inducible cell lines, from a cohort of 91 mature B-cell lymphomas and from sorted germinal-center B-cells. By this approach, we identified 13 lncRNAs differentially expressed in IG-MYC-positive Burkitt lymphoma and regulated by MYC in the model cell lines. Among them we focused on a lncRNA that we named MINCR, showing a strong correlation with MYC expression in MYC-positive lymphomas and in pancreatic ductal adenocarcinomas. RNAi experiments showed that MINCR controls cellular viability by influencing the expression of MYC-regulated cell cycle genes. Finally we provide evidences that down-regulation of AURKA, AURKB and CTD1 may explain the reduction in cellular proliferation observed upon MINCR knock-down. We therefore suggest that MINCR acts as a modulator of MYC transcriptional control of cell cycle genes.

Study EGAS00001001199

Epigenome and transcriptome profiling of chronic lymphocytic leukemia patients

Chronic lymphocytic leukemia (CLL) is characterized by substantial clinical heterogeneity, despite relatively few genetic alterations. To provide a basis for studying epigenome deregulation in CLL, we established genome-wide chromatin accessibility maps for 88 CLL samples from 55 patients using the ATAC-seq assay, and we also performed ChIPmentation and RNA-seq profiling for ten representative samples. Based on the resulting dataset, we devised and applied a bioinformatic method that links chromatin profiles to clinical annotations. Our analysis identified sample-specific variation on top of a shared core of CLL regulatory regions. IGHV mutation status – which distinguishes the two major subtypes of CLL – was accurately predicted by the chromatin profiles, and gene regulatory networks inferred for IGHV-mutated vs. IGHV-unmutated samples identified characteristic differences between these two disease subtypes. In summary, we discovered widespread heterogeneity in the chromatin landscape of CLL, established a community resource for studying epigenome deregulation in leukemia, and demonstrated the feasibility of chromatin accessibility mapping in cancer cohorts and clinical research.

Study EGAS00001001821

Epigenetic dynamics of monocyte to macrophage differentiation

Monocyte to macrophage differentiation involves major biochemical and structural changes in non-dividing cells. In order to elucidate the role of gene regulatory changes during this process, we used high-throughput sequencing to analyze the complete transcriptome and epigenome of human monocytes that were isolated by elutriation and differentiated in vitro by addition of MCSF in serum-free medium. We also investigated the effect of loading the macrophages with modified LDL. We found that many mRNAs and miRNAs were significantly up- or downregulated during differentiation. While there was no correlation between gene expression and DNA methylation changes at transcription start sites, we identified a large number of intra- and intergenic regions that rapidly lost DNA methylation, became nucleosome-free and gained histone marks indicative of active enhancers. Loading of macrophages with modified LDL caused gene expression changes, but no chromatin changes. In summary, our results demonstrate that monocyte to macrophage differentiation is associated with rapid, highly targeted epigenetic changes, whereas lipid uptake mainly affects regulatory circuits of soluble factors.

Study EGAS00001001595

Whole genome, transcriptome and methylome profiling enhances actionable target discovery in high-risk paediatric cancer

Zero Childhood Cancer is a precision medicine program to benefit children with poor-outcome, rare, relapsed or refractory cancer. Utilising tumour and germline whole genome sequencing (WGS) and RNA sequencing (RNAseq) across 252 tumours from high-risk paediatric cancer patients, we identified 968 reportable molecular aberrations (39.9% in WGS and RNAseq, 35.1% WGS-only, 25.0% RNAseq-only). 93.7% of patients had at least one germline or somatic aberration, 71.4% had therapeutic targets and 5.2% had a change in diagnosis. WGS identified pathogenic cancer-predisposing variants in 16.2% of patients. In 76 CNS tumours, methylome analysis confirmed diagnosis in 71.1% and contributed to a change of diagnosis in two cases (2.6%). To date 43 patients have received a recommended therapy, 38 of whom could be evaluated. A small but encouraging proportion of 31% showed some evidence of clinical benefit. Comprehensive molecular profiling resolved the molecular basis of virtually all high-risk cancers, which in some cases has significant clinical impact.

Study EGAS00001004572

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