Search Results - EGA European Genome-Phenome Archive

Integrative genomic analysis identifies key pathogenic mechanisms in primary mediastinal large B-cell lymphoma

Primary mediastinal large B-cell lymphoma (PMBL) represents a clinically and pathologically distinct subtype of large B-cell lymphomas. Furthermore, molecular studies, including global gene expression profiling, have provided evidence that PMBL is more closely related to classical Hodgkin lymphoma (cHL). Although targeted sequencing studies have revealed a number of mutations involved in PMBL pathogenesis, a comprehensive description of disease-associated genetic alterations and perturbed pathways is still lacking. Here, we performed whole-exome sequencing of 95 PMBL tumors to inform on oncogenic driver genes and recurrent copy number alterations. The integration of somatic gene mutations with gene expression signatures provides further insights into genotype-phenotype interrelation in PMBL. We identified highly recurrent oncogenic mutations in the JAK-STAT and NF-kB pathways, and provide additional evidence of the importance of immune evasion in PMBL (CIITA, CD58, B2M, CD274, PDCD1LG2). Our analyses highlight the IRF-pathway as a putative novel hallmark with frequent alterations in multiple pathway members (IRF2BP2, IRF4, IRF8). In addition, our integrative analysis illustrates the importance of JAK1, RELB and EP300 mutations driving oncogenic signaling. The identified driver genes were significantly more frequently mutated in PMBL as compared to diffuse large B-cell lymphoma, whereas only a limited number of genes were significantly different between PMBL and cHL, emphasizing the close relationship between these entities. Our study, performed on a large cohort of PMBL, highlights the importance of distinctive genetic alterations for disease taxonomy with relevance for diagnostic work-up and therapeutic decision-making.

Study EGAS00001003746

Colorectal cancer study

Matrix metalloproteinase-11 (MMP11) is an enzyme with proteolytic activity against matrix and non-matrix proteins. Although most MMPs are secreted as inactive proenzymes and they are later activated extracellularly, MMP11 is activated intracellularly by furin within the constitutive secretory pathway. It is a key factor in physiological tissue remodeling and its alteration may play an important role in the progression of epithelial malignancies and other diseases. TCGA colon and colorectal adenocarcinoma data showed that upregulation of MMP11 expression correlates with tumorigenesis and malignancy. Here, we provide evidence that a germline variant in the MMP11 gene (NM_005940: c.232C>T; p.(Pro78Ser)), identified by whole exome sequencing, can increase the tumorigenic properties of colorectal cancer (CRC) cells. P78S is located in the prodomain region, which is responsible for blocking MMP11’s protease activity. This variant was detected in the proband and all the cancer-affected family members analyzed, while it was not detected in healthy relatives. In silico analyses predict that P78S could have an impact on the activation of the enzyme. Furthermore, our in vitro analyses show that the expression of P78S in HCT116 cells increases tumor cell invasion and proliferation. In summary, our results show that this variant could modify the structure of the MMP11 prodomain, producing a premature or uncontrolled activation of the enzyme that may contribute to an early CRC onset in these patients. The study of this gene in other CRC cases will provide further information about its role in CRC development, which might improve patient treatment in the future.

Study EGAS00001006489

Robust methylation-based classification of brain tumours using nanopore sequencing

Background: DNA methylation-based classification of cancer provides a comprehensive molecular approach to diagnose tumours. In fact, DNA methylation profiling of human brain tumours already profoundly impacts clinical neuro-oncology. However, current implementations using hybridization microarrays are time-consuming and costly. We recently reported on shallow nanopore whole-genome sequencing for rapid and cost-effective generation of genome-wide 5-methylcytosine profiles as input to supervised classification. Here, we demonstrate that this approach allows to discriminate a wide spectrum of primary brain tumours. Results: Using public reference data of 82 distinct tumour entities, we performed nanopore genome sequencing on N=382 tissue samples covering 46 brain tumour (sub)types. Using bootstrap sampling in a cohort of N = 56 cases, we find that a minimum set of 1,000 random CpG features is sufficient for high-confidence classification by ad hoc random forests. We implemented score recalibration as confidence measure for interpretation in a clinical context and empirically determined a platform-specific threshold in a randomly sampled discovery cohort (N = 185). Applying this cut-off to an independent validation series (N = 184) yielded 148 classifiable cases (sensitivity 80.4%) and demonstrated 100 % specificity. Cross-lab validation demonstrated robustness with concordant results across four laboratories in 10/11 (90.9%) cases. In a prospective benchmarking (N = 15), median time to results was 21.1 hours. Conclusions: In conclusion, nanopore sequencing allows robust and rapid methylation-based classification across the full spectrum of brain tumours. Platform-specific confidence scores facilitate clinical implementation for which prospective evaluation is warranted and ongoing.

Study EGAS00001006540

Transcriptional_reprogramming_from_innate_immune_functions_to_a_pro_thrombotic_signature_upon_SARS_CoV_2_sensing_by_monocytes_in_COVID_19

Alterations in the myeloid immune compartment have been observed in COVID-19, but the specific mechanisms underlying these impairments are not completely understood. Here we examined the functionality of classical CD14+ monocytes as a main myeloid cell component in well-defined cohorts of patients with mild and moderate COVID-19 during the acute phase of infection and compared them to that of healthy individuals. We found that ex vivo isolated CD14+ monocytes from mild and moderate COVID-19 patients display specific expression patterns of costimulatory and inhibitory receptors that clearly distinguish them from healthy monocytes, as well as an altered metabolic profile. In addition, decreased NFB activation in COVID-19 monocytes ex vivo is accompanied by an intact type I IFN antiviral response. Secondary pathogen sensing ex vivo led to a state of functional unresponsiveness characterized by a defect in pro-inflammatory cytokine expression, NFB-driven cytokine responses and defective type I IFN response in moderate COVID-19 monocytes, together with defects in the metabolic reprogramming that innate immune cells usually undergo upon pathogen sensing. Transcriptionally and functionally, COVID-19 monocytes switched their gene expression signature from canonical innate immune functions to a pro-thrombotic phenotype characterized by enrichment of pathways involved in hemostasis, immunothrombosis, platelet aggregation and other accessory pathways to platelet activation, accumulation and clot formation, including extracellular matrix reorganization, integrin cell surface interactions and signaling by PDGF. These results provide a potential mechanism by which innate immune dysfunction in COVID-19 may contribute to disease pathology

Study EGAS00001006788

Non-viral precision T cell receptor replacement for personalized cell therapy

The T cell receptor (TCR) provides the fine specificity of T cells to recognize mutations in cancer cells 1-3. We developed a clinical-grade approach based on CRISPR/Cas9 non-viral precision genome editing to simultaneously knock-out the two endogenous TCR genes, TCRα (TRAC) and TCRβ (TRBC), and insert in the TRAC locus the two chains of a neoantigen-specific TCR (neoTCR), isolated from the patient’s own circulating T cells using a personalized library of soluble predicted neoantigen-HLA capture reagents. Sixteen patients with refractory solid cancers received up to three distinct neoTCR-transgenic cell products, each expressing a patient-specific neoTCR, in a cell dose-escalation, first-in-human phase 1 clinical trial (NCT03970382). One patient had grade 1 cytokine release syndrome, and one grade 3 encephalitis. All had the expected side effects from the lymphodepleting chemotherapy. Five patients had stable disease, and the other 11 had disease progression as best response on therapy. NeoTCR-transgenic T cells were detected in tumour biopsies post-infusion at frequencies higher than the native TCRs pre-infusion. This study demonstrates the feasibility of isolating and cloning multiple TCRs recognizing mutational neoantigens, the simultaneous knock-out of the endogenous TCR and knock-in of the neoTCRs using single-step, non-viral precision genome editing, the manufacturing of neoTCR engineered T cells at clinical grade, the safety of infusing up to three gene edited neoTCR T cell products, and the ability of the transgenic T cells to traffic to the patients’ tumours.

Study EGAS00001006898

Chronic lymphocytic leukemia IGHV somatic hypermutation detection by targeted capture next-generation sequencing

Somatic hypermutation (SHM) status of the immunoglobulin heavy variable (IGHV) gene locus plays a crucial role in determining the prognosis and treatment of patients with chronic lymphocytic leukemia (CLL). A common approach for determining SHM status is multiplex PCR of the IGH gene followed by Sanger sequencing; however, this technique is low throughput, vulnerable to failure, and does not allow multiplexing with other molecular diagnostic assays. Here we designed and validated a DNA targeted capture approach that allows the assessment of IGHV SHM status as a sub-module of a larger next-generation sequencing (NGS) assay. We developed an end-to-end assay that takes as input raw FASTQ files and outputs a report containing IGHV SHM status and V-allele usage following the guidelines of the European Research Initiative on CLL (ERIC). We validated the approach on 35 CLL patient samples, 34 of which were previously characterized using Sanger sequencing. The targeted capture NGS panel identified the SHM status of 34 of 35 CLL patients. We showed 100% sensitivity and specificity among the 33 CLL samples with both NGS and Sanger calls. Furthermore, we demonstrated that this panel can be combined with additional targeted capture panels to detect common and prognostically important CLL single nucleotide variants (SNV) and insertion/deletion (indel) variants as well as copy number variants (del17p). Thus, a targeted capture approach to IGHV SHM detection can be easily integrated into broader sequencing panels, allowing broad CLL prognostication in a single molecular assay.

Study EGAS00001006887

PD-L1 blockade in combination with carboplatin as immune induction in metastatic lobular breast cancer: the GELATO-trial

Invasive lobular breast cancer (ILC) is the second most common histological breast cancer subtype but published data on trials specific for ILC are so far lacking. Translational research revealed that a subset of ILCs may be immune-related and more sensitive to DNA-damaging agents such as platinum. In murine ILC models, synergy between immune checkpoint blockade and platinum has been observed. Here, we tested this concept in the phase II, GELATO-trial (NCT03147040), in which patients with metastatic ILC were treated with weekly carboplatin (AUC 1.5) as immune induction treatment for 12 weeks and atezolizumab (PD-L1 blockade; every three weeks) from the third week onwards until disease progression. Four out of 23 evaluable patients had a partial response (17%, 95%CI 5-39%) and two patients had stable disease for at least 24 weeks, resulting in a clinical benefit rate of 26% (95%CI 10-48%). Out of these six patients, four patients had triple-negative ILC (TN-ILC). In serial biopsies of metastatic lesions, we observed higher CD8 T-cell infiltration, expression of immune checkpoints, and exhausted T cells upon carboplatin/PD-L1 blockade. This is the first report of a clinical trial specifically for ILC and we demonstrate promising anti-tumor activity of atezolizumab with carboplatin as immune induction, in particular for TN-ILC. While activity of carboplatin/PD-L1 blockade in classical ER+ ILC was limited, our translational data yield important insights for the design of highly needed clinical trials in ILC.

Study EGAS00001006902

Gut metagenome from Estonian Microbiome Cohort

Stool samples were collected from 2,509 Estonian Biobank participants. The shotgun metagenomic paired-end sequencing was performed by Novogene Bioinformatics Technology Co., Ltd. using the Illumina NovaSeq6000 platform, resulting in 4.62 ± 0.44 Gb of data per sample (insert size, 350 bp; read length, 2 × 250 bp). A total of 2,513 samples belonging to 2,509 individuals were sequenced, including 4 biological replicates from one individual. First, the reads were trimmed for quality and adapter sequences. The host reads that aligned to the human genome were removed using SOAP2.21 (parameters: -s 135 -l 30 -v 7 -m 200 -x 400).

Dataset EGAD00001008448

Clonal selection after gene therapy in sickle cell disease

While gene therapy (GT) provides a potentially curative treatment option for patients with sickle cell disease (SCD), the occurrence of myeloid malignancies in clinical trials has prompted concern. To interrogate potential mechanisms underlying increased cancer risk, we used hematopoietic stem cell (HSC) clonal tracking by whole genome sequencing (WGS) to map the somatic mutation and clonal landscape of 2,592 gene modified as well as unmodified single stem and progenitor cells from six SCD patients undergoing gene therapy (7-26 years old, average 12.7× depth). Pre-GT phylogenetic trees in SCD were highly polyclonal and mutation burdens per cell were elevated in some, but not all, patients. Post-GT, no clonal expansions were identified. However, an increased frequency of driver mutations associated with myeloid neoplasms or clonal hematopoiesis (DNMT3A- and EZH2-mutated clones in particular) were seen in both genetically modified and unmodified cells suggested positive selection of mutant clones during gene therapy. This work sheds light on the mutation landscape and HSC clonal dynamics in gene therapy for SCD and highlights enhanced fitness of some HSCs harboring pre-existing driver mutations following gene therapy. Future studies should define the long-term fate of mutant clones including any contribution to expansions associated with myeloid neoplasms.

Dataset EGAD00001010913

RNAseq data for Failure of Differentiation of the Rhombic Lip Constitutes Medulloblastoma

We used single-cell transcriptomics to study cells from the developing human cerebellum, and show that different molecular subgroups of medulloblastoma resemble distinct glutamatergic progenitors.

Dataset EGAD00001008458

KiCS WGS data for academic and for-profit use

Data from samples that are marked for both academic and for-profit use.

Dataset EGAD00001009699

Myeloma Genome Project Targeted Panel Validation dataset

372 samples consisting of 185 patient paired CD138+ tumor and non-involved DNA pairs, plus 5 Horizon Diagnostic known mutation standards (HD). Samples were processed using the KAPA HyperCap protocol and hybridized onto a targeted panel for multiple myeloma and associated diseases. Reference Sudha et al Clinical Cancer Research, 2022.

Dataset EGAD00001008689

Irish Covid19 WGS Alignment Data

Dataset contains 483 Irish origin Individuals with Covid19. For WGS, Alignment has been done using BWA-mem (sention v 201808.03 ) and BAM file generated.

Dataset EGAD00001010098

Targeted and shallow whole genome sequencing identifies therapeutic opportunities in p53abn endometrial cancers

Purpose: Shallow whole genome sequencing (sWGS) can detect copy number (CN) aberrations. In high-grade serous ovarian (HGSOC) sWGS identified CN signatures such as homologous recombination deficiency (HRD) to direct therapy. We applied sWGS with targeted sequencing to p53abn endometrial cancers (ECs) to identify additional prognostic stratification and therapeutic opportunities. Experimental Design: sWGS and targeted panel sequencing was performed on formalin-fixed paraffin-embedded p53abn ECs. CN alterations, mutational data and CN signatures were derived, and associations to clinicopathologic and outcomes data were assessed. Results: In 187 p53abn ECs, 5 distinct CN signatures were identified. Signature 5 was associated with BRCA1/2 CN loss with features similar to HGSOC HRD signature. 22% potential HRD cases were identified, 35 patients with signature 5, and 8 patients with BRCA1/2 somatic mutations. Signatures 3 and 4 were associated with whole genome duplication, and CCNE1, ERBB2 and MYC amplifications, with mutations in PIK3CA enriched in signature 3. We observed improved overall survival (OS) for patients with signature 2 and worse OS for signatures 1 and 3. 28% of patients had CCNE1 amplification and this subset was enriched with carcinosarcoma histotype. 34% of patients, across all histotypes, had ERBB2 amplification and/or HER2 overexpression on immunohistochemistry, which was associated with worse outcomes. Mutations in PPP2R1A (29%) and FBXW7 (16%) were among the top 5 most common mutations. Conclusions: sWGS and targeted sequencing identified therapeutic opportunities in 75% of p53abn EC patients. Further research is needed to determine the efficacy of treatments targeting these identified pathways within p53abn ECs.

Study EGAS00001007661

Spatiotemporal evolution and inter-patient heterogeneity in primary and recurrent/metastatic head and neck squamous cell carcinoma

Head and neck cancer squamous cell carcinomas (HNSCCs) are heterogeneous in terms of origin and aetiology. In addition, there is uncertainty about the spatiotemporal genetic evolution from initial diagnosis to recurrence/metastasis (R/M) after primary treatments and further disease progression following systemic treatment. Changes in the genetic profile have implications on the selection of appropriate treatments for patients, especially in the era of targeted therapies and immunotherapies. Here, we analysed a cohort of 11 HNSCC patients with metachronous R/M, among whom nine had paired primary and R/M samples suitable for next-generation sequencing (multiple R/M samples collected at different time points were available for some of the patients). At the genomic level, the R/M samples shared a fraction of the somatic single nucleotide variants (SNVs) with the index primary tumours, but they also acquired many additional mutations, while losing only a few others. A similar behaviour was also observed when examining the changes of mutational signatures between primary and R/M samples. Overall, R/M appeared thus more genetically diverse than the respective primary tumours. The transcriptomic analysis showed that R/M samples had lower immune cell infiltration and several genes related to immune response were significantly downregulated compared to the primary samples. Our results underline the importance of analysing multiple samples per patient to obtain a more complete picture of the patient’s tumour and advocates a re-biopsy in the event of R/M and treatment failure, in order to select the most appropriate therapeutic strategy.

Study EGAS00001007464

Benchmarking for alignment and variant calling

Background: Lung cancer is a heterogeneous disease and the primary cause of cancer-related mortality worldwide. Somatic mutations, including large structural variants, are important biomarkers in lung cancer for selecting targeted therapy. Genomic studies in lung cancer have been conducted using short-read sequencing. Emerging long-read sequencing technologies are a promising alternative to study somatic structural variants, however there is no current consensus on how to process data and call somatic events. In this study, we preformed whole genome sequencing of lung cancer and matched non-tumour samples using long and short read sequencing to comprehensively benchmark three sequence aligners and six structural variant callers comprised of four generic callers (Sniffles2, cuteSV, SVIM and DELLY in generic mode) and two somatic callers (nanomonsv and DELLY in somatic modes). Results: Different combinations of aligners and variant callers influenced somatic structural variant detection. The choice of caller had a significant influence on somatic structural variant detection in terms of variant type, size, sensitivity, and accuracy. The performance of each variant caller was assessed by comparing to somatic structural variants identified by short read sequencing. When compared to somatic structural variants detected with short read sequencing, more events were detected with long read sequencing. The mean recall of somatic variant events identified by short read sequencing was higher for the somatic callers (64%) than generic callers (52%), with nanomonsv (69%) showing the best performance. Conclusion: Long read sequencing can identify somatic structural variants. The longer reads have the potential to improve our understanding of cancer development and inform personalized cancer treatment.

Study EGAS00001007819

High-Resolution Spatial Transcriptomics Uncover Epidermal-Dermal Divergences in Merkel Cell Carcinoma: Spatial Context Reshapes the Gene Expression Landscape

Merkel cell carcinoma (MCC) is an aggressive malignancy with neuroendocrine differentiation marked by high plasticity, often manifesting as rapid therapy resistance. Although the cell-of-origin is presumed to be epithelial, epidermal localization of MCC is rarely observed, largely because in situ MCC is typically an incidental finding. Nevertheless, a subset of MCC tumors exhibits epidermotropism, wherein tumor cells are present in the epidermis. The behavior of cancer cells is profoundly influenced by the tumor microenvironment and interactions with neighboring cells. Notably, the normal counterparts of the cancer’s cell-of-origin have been shown to attenuate tumor aggressiveness. Thus, epidermotropic MCC presents a unique opportunity to explore the potential role of surrounding keratinocytes in modulating tumor cell behavior. While the epidermotropic tumor nests share histological resemblance with their dermal counterparts, their transcriptomic profiles remain unexplored. Here, we employed high-definition spatial and single cell transcriptomics to dissect the gene expression profiles of epidermotropic MCC cells, comparing them to MCC cells in the tumor core and those adjacent to blood vessels. Notably, epidermotropic MCC cells exhibit a transcriptomic signature reminiscent of cutaneous squamous cell carcinoma, characterized by upregulation of genes encoding keratins, S100A proteins, as well as calmodulin-like proteins 3 and 5. Mechanistically, this keratinocytic differentiation is associated with enhanced p63 activity, leading to the upregulation of PERP. Collectively, our study demonstrates that MCC cells can adopt a keratinocytic differentiation program in response to microenvironmental cues, underscoring the remarkable phenotypic plasticity of this malignancy and the importance of the tumor microenvironment for tumor characteristics.

Study EGAS00001008157

Capturing disease severity in LIS1-lissencephaly reveals proteostasis dysregulation in patient-derived forebrain organoids

Lissencephaly is a developmental cortical malformation characterized by reduced to absent gyri and a disorganized cortex, often leading to severe impairments in affected individuals and a reduced life expectancy. Heterozygous mutations in the LIS1 gene, encoding a regulator of the microtubule motor dynein, cause lissencephaly with different clinical severities. While the clinical disease spectrum correlates with the degree of lissencephaly, location and type of mutation may not. We leveraged forebrain-type organoids from LIS1-lissencephaly patients, diagnosed with mild, moderate or severe lissencephaly to investigate, in a cytoarchitecture and multi-omics approach, how the severity degree in patients might relate to specific mutations in the LIS1 gene. We questioned which processes during cortical development might be differentially affected by severity grade, and whether they could be pharmacologically targeted. We found alterations in neurodevelopment often with a severity-dependent gradient. Specifically, we identified alterations of the cytoarchitecture, progenitor cell homeostasis and neurogenesis. Particularly important disease-linked molecular mechanisms were microtubule destabilization, WNT-signaling, and perturbed cadherin- and unfolded protein-binding. Some mechanisms exhibited a severity-dependent gradient, or were specific to a severe grade. We present strategies to reverse phenotypic changes in LIS1-patient organoids, and an in silico approach with therapeutic potential. Thus, we show that different LIS1-severity grades can be recapitulated in vitro, that there is a direct link between the phenotype and genotype, that organoid-based disease modeling can identify molecular underpinnings of malformations of cortical development and that organoids provide a valid platform to develop and test therapeutic strategies.

Study EGAS00001008227

Immunodeficiency syndrome caused by LCP1 mutations

Severe congenital neutropenia (SCN) is characterized by neutropenia, recurrent infections and an increased leukemia risk. Multiple genetic defects underlying SCN have been identified, but a genetic diagnosis is still lacking in a significant proportion of patients. Here, we report three independent pedigrees with autosomal dominant variants in LCP1. Variants c.740-1G>T and c.740-20_744del resulted in the same alternatively spliced RNA product, causing an in-frame deletion (p.A247_E254del). Variant c.509C>T in the third pedigree resulted in p.S170L. Variant carriers suffer from neutropenia, poor or complete lack of response to G-CSF treatment, and variable degrees of lymphopenia. Patients with A247_E254del presented with tetraploid cells in the bone marrow, indicative of disturbed cytokinesis. In one of these kindreds, two individuals developed acute leukemia. G-CSF non-responsiveness and defective cell cycling were repaired upon correction of the LCP1 A247_E254del variant in patient-derived induced pluripotent stem cells, supporting the monogenic origin of the disease. Indicative of their gain-of-function, both A247_E254del and S170L variants increased F-actin bundling and formation of abnormal protrusions. Single-cell transcriptome analysis of A247_E254del bone marrow-derived hematopoietic stem and progenitor cells (HSPCs) showed deregulation of signaling pathways controlling mitosis in multi-lineage and lymphoid-primed HSPC subsets. We conclude that activating LCP1 variants cause a new autosomal dominant hematopoietic disorder. Depending on the consequences of the LCP1 variants for protein structure, patients may suffer from G-CSF refractory severe neutropenia, lymphopenia, defective cytokinesis and predisposition to leukemia.

Study EGAS00001008293

Epigenome-wide methylation analysis of colorectal carcinoma, adenoma and normal tissue reveals novel biomarkers addressing unmet clinical needs

Studies about CRC biomarker discovery have focused on methylation patterns in normal and colorectal tumor tissue, leading to a lack of knowledge of methylation in adenomas. Therefore, we performed the first epigenome-wide study to compare the epigenomes of all three tissue types combined, and to identify discriminatory biomarkers. Public Illumina MethylEPIC® data was collected from 552 normal, 118 carcinoma and 116 adenoma samples. Pairwise analyses were performed for discovery of differentially methylated probes (DMPs). We identified 693 813, 620 643 and 558 897 DMPs when comparing normal vs carcinoma, normal vs adenoma and adenoma vs carcinoma respectively. To double evidence (DE) these DMPs, analysis of Illumina 450K data from public datasets was performed. Through this analysis, 13 DE DMPs with │Δβ│≥0.3 were identified for adenoma vs carcinoma. A binary logistic regression model was generated to evaluate the discriminatory potential of these DE DMPS. The model was validated in an in-house experimental methylation dataset of 13 adenoma and 9 carcinoma samples. Our classifier reached a cross-validated AUC of 0.996 and 0.855 in the discovery and validation datasets respectively. A sensitivity and specificity of 96% and 95% were reached, with an overall accuracy of 96%. Our analysis show that methylation biomarkers have the potential to discriminate between normal, precursor and carcinoma tissues of the colorectum. More importantly, we highlight the power of the methylome, showing that DMPs can be used as biomarkers in the clinic to identify colorectal adenoma and carcinoma.

Study EGAS00001007017

A novel transcriptional signature identifies T-cell infiltration in high-risk paediatric cancer

Background Molecular profiling of the tumour immune microenvironment (TIME) has enabled the rational choice of immunotherapies in some adult cancers. In contrast, the TIME of paediatric cancers is relatively unexplored. We speculated that a more refined appreciation of the TIME in childhood cancers, rather than a reliance on commonly used biomarkers such as tumour mutation burden (TMB), neoantigen load and PD-L1 expression, is an essential prerequisite for improved immunotherapies in childhood solid cancers. Methods We combined immunohistochemistry (IHC) with RNA-sequencing and whole genome sequencing across a diverse spectrum of high-risk paediatric cancers to develop an alternative, expression-based signature associated with CD8+ T-cell infiltration of the TIME. Further, we explored transcriptional features of immune archetypes, T-cell receptor sequencing diversity, assessed the relationship between CD8+ and CD4+ abundance by IHC and deconvolution predictions, and assessed common adult biomarkers such as neoantigen load and TMB. Results A novel 15-gene immune signature, Immune Paediatric Signature Score (IPASS), was identified. Using this signature, we estimate up to 31% of high-risk cancers harbour infiltrating T-cells. In addition, we showed that PD-L1 protein expression is poorly correlated with PD-L1 RNA expression and TMB and neoantigen load are not predictive of T-cell infiltration in paediatrics. Furthermore, deconvolution algorithms are only weakly correlated with IHC measurements of T-cells. Conclusions Our data provides new insights into the variable immune-suppressive mechanisms dampening responses in paediatric solid cancers. Effective immune-based interventions in high-risk paediatric cancer will require individualised analysis of the TIME.

Study EGAS00001007029

Treatment stratification and biomarker validation using patient-derived head and neck cancer organoids

Background Organoids are three-dimensional structures that can be grown from patient-derived material including carcinomas. These in vitro models can be cryopreserved to generate “living” biobanks that reflect patient heterogeneity. Head and neck cancer (HNC) is a collective term used for tumors arising in the head and neck area, including squamous cell carcinomas (HNSCC) and adenocarcinoma of the salivary gland. Methods to culture patient-derived HNC organoids have previously been described. Methods Organoids were derived from resection or biopsy material of patients included between 2016 and 2022. Organoids were characterised with immunohistochemistry and whole exome sequencing (WES) and exposed to chemo-, radio- and targeted-therapies. CRISPR/Cas9-based gene editing was applied to validate proposed biomarkers. Results We have extended our previously published organoid biobank to a total of 110 organoid models, some of which were characterised by histology and WES. Organoids recapitulated both single nucleotide variants and copy number alterations as found in patient HNSCC samples. Organoid and patient response to radiotherapy (RT; primary (n=6) and adjuvant (n=15)) could be compared in 21 HNC cases. In the adjuvant RT group, organoids derived from patients that relapsed were more resistant to RT in vitro, showing potential for guiding treatment options in this subset of patients. Conclusion Taken together, these results indicate illustrate the potential of organoids as a diagnostic tool in personalised medicine for HNC and indicate the potential of this technology for biomarker discovery and validation within the context of relevant patient heterogeneity.

Study EGAS00001007076

Whole Exome Sequencing data of six chRCC tumors corresponding to three patients

Mammalian target of rapamycin (mTOR) is a central regulator of mammalian metabolism and physiology. Aberrant hyperactivation of the mTOR pathway promotes tumor growth and metastasis, and can also promote tumor resistance to chemotherapy and cancer drugs; this makes mTOR an attractive cancer therapeutic target. mTOR inhibitors have been approved to treat cancer; however, the mechanisms underlying drug sensitivity remain poorly understood. Here, whole exome sequencing of three chromophobe renal cell carcinoma (chRCC) patients with exceptional mTOR inhibitor sensitivity revealed that all three patients shared somatic mutations in the deubiquitinase USP9X. The clonal characteristics of the mutations, which were amassed by studying multiple patients’ primary and metastatic samples from various years, together with the low USP9X mutation rate in unselected chRCC series, reinforced a causal link between USP9X and mTOR inhibitor sensitivity. Rapamycin treatment of USP9X-depleted HeLa and renal cancer 786-O cells, along with the pharmacological inhibition of USP9X, confirmed that this protein plays a role in patients’ sensitivity to mTOR inhibition. USP9X was not found to exert a direct effect on mTORC1, but subsequent ubiquitylome analyses identified p62 as a direct USP9X target. Increased p62 ubiquitination and the augmented rapamycin effect upon bortezomib treatment, together with the results of p62 and LC3 immunofluorescence assays, suggested that dysregulated autophagy in USP9X-depleted cells can have a synergistic effect with mTOR inhibitors. In summary, we show that USP9X constitutes a potential novel marker of sensitivity to mTOR inhibitors in chRCC patients, and represents a clinical strategy for increasing the sensitivity to these drugs.

Study EGAS00001007104

A Machine Learning Tool Integrating Circulating Cell-Free DNA Methylation with Clinical Variables for Non-Invasive Diagnosis of Liver Graft Pathology

Liver Transplant Recipients (LTRs) with elevated liver enzymes can develop graft injury due to various etiologies, such as T-cell mediated rejection (TCMR) and NASH (NASH-LT). While liver biopsy is the gold standard method for diagnosis of graft pathology, it is invasive and is associated with risks. The goal of our study was to develop a Machine Learning (ML) tool integrating clinical variables with methylation patterns on circulating DNA in plasma as a non-invasive diagnostic tool of graft injury. We generated methylation profiles of circulating DNA in a pilot study of 43 LTRs (11 NASH-LT, 19 TCMR, and 13 Control-LT), and developed an L2 multinomial logistic regression ML approach across 101 bootstrapped models to distinguish between the graft conditions. NASH was associated with distinctive methylation patterns on genes involved in fatty acid metabolism, while methylation of platelet-derived growth factors was identified in patients with TCMR. Our ML model achieved a mean multi-classification accuracy of 0.91, with mean specificity and sensitivity of 0.94 and 0.91, respectively. The model was found to be particularly adept at detecting TCMR and Control-LT, with true positive rates (TPRs) of 95% and 90%, and areas under the curve (AUROC) of 0.992 and 0.985, respectively. For NASH-LT, the models achieved a performance with a TPR of 82% and an AUROC of 0.991. These preliminary results suggest that our newly developed ML tool, leveraging cell-free DNA methylation and clinical variables, is a promising non-invasive classifier of graft pathology.

Study EGAS00001007171

scRNAseq for patients with immunodeficiency and HCs

The NFAT family of transcription factors plays central roles in adaptive immunity in murine models, however, their contribution to human immune homeostasis remains poorly defined. In a multigenerational pedigree, we identified three patients carrying germline biallelic missense variants in NFATC1, presenting with recurrent infections, hypogammaglobulinemia and decreased antibody responses. The compound heterozygous NFATC1 variants identified in the patients caused decreased stability and reduced binding of DNA and interacting proteins. We observed defects in early activation and proliferation of T and B cells from these patients, amenable to reconstitution upon genetic rescue. Following stimulation, T-cell activation and proliferation were impaired, reaching that of healthy controls with delay indicative of an adaptive capacity of the cells. Assessment of the metabolic capacity of patient T cells, revealed that NFATc1-dysfunction rendered T cells unable to engage in glycolysis following stimulation, although oxidative metabolic processes were intact. We hypothesized that NFATc1-mutant T cells could compensate for the energy deficit due to defective glycolysis by enhanced lipid metabolism as an adaptation, leading to a delayed, but not lost activation responses. Indeed, we observed increased 13C-labelled palmitate incorporation into citrate indicating higher fatty acid oxidation and we demonstrated that metformin and rosiglitazone improved patient T-cell effector functions. Collectively, enabled by our molecular dissection of NFATC1 mutations and extending the role of NFATc1 in human immunity beyond receptor signaling, and reveal evidence of metabolic plasticity in the context of impaired glycolysis observed in patient T cells to remedy delayed effector responses.

Study EGAS00001007271

Analysis of the Elements Involved in the Enrichment of a Panel of Genomic Regions by Nanopore Sequencing Using Adaptive Sampling

DNA sequencing using nanopore technologies with the affordable MinION device is useful for the identification and characterization of structural variants, long haplotypes, sequencing of repetitive regions and identification of epigenetic modifications. The main limitation of this approach is the low coverage obtained, which might be avoided by adaptive sampling, a computationally controlled method of enrichment for targeted genomic regions. This study dissects the factors involved in the enrichment by adaptive sampling of a panel of 18 human genome regions containing 20 genes implicated in breast cancer sequenced in 16 patients with familial breast cancer negative for NGS screening. An average coverage of 2.0x was obtained for the whole genome and 5.1x for selected regions. Sequencing time was the main factor improving coverage. The selection of long reads (&gt;1 Kb) did not improve the enrichment. The length of the selected region, which in our study ranged from 126 to 565 Kb, did not play a significant role in enrichment. However, the region containing PMS2 showed significantly lower coverage, which could be explained by the high number of PMS2 pseudogenes (N = 14), which were also enriched. Our study shows new evidence of enrichment obtained by adaptive sampling in a panel of genomic regions and shows parameters, the relevance of sequencing time and the role of pseudogenes, that improve the enrichment yield with no library reloading or GPU use, data useful for a more efficient application of this procedure in future studies.

Study EGAS00001007375

Efficacy of nivolumab in pediatric cancers with high mutation burden and mismatch-repair deficiency

Purpose: Checkpoint-inhibitors have limited efficacy for children with unselected solid and brain tumors. We report the first prospective pediatric trial (NCT02992964) using nivolumab exclusively for refractory non-hematological cancers harboring tumor mutation burden (TMB) ≥5 mutations/megabase (mut/Mb) and/or mismatch-repair deficiency (MMRD). Patients and methods: Twenty patients were screened, and ten ultimately included in the response cohort of whom nine had TMB >10mut/Mb (three initially eligible based on MMRD) and one patient had TMB between 5-10 mut/Mb. Results: Delayed immune responses contributed to best overall response of 50%, improving on initial objective responses (20%) and leading to 2-year overall survival (OS) of 50% (95% CI; 27, 93). Four children, including three with refractory malignant gliomas are in complete remission at a median follow-up of 37-months (range: 32.4-60), culminating in 2-year OS of 43% (95% CI; 18.2, 100). Biomarker analyses confirmed benefit in children with germline MMRD, microsatellite instability, higher activated and lower regulatory circulating T-cells. Stochastic mutation accumulation driven by underlying germline MMRD impacted the tumor microenvironment, contributing to delayed responses. No benefit was observed in the single patient with a MMR-proficient tumour and TMB 7.4 mut/Mb. Conclusions: Nivolumab resulted in durable responses and prolonged survival for the first time in a pediatric trial of refractory hypermutated cancers including malignant gliomas. Novel biomarkers identified here need to be translated rapidly to clinical care to identify children who can benefit from checkpoint-inhibitors, including for upfront management of their cancers.

Study EGAS00001007393

shallow WGS and deep targeted panel on ctDNA in rhabdomyosarcomas

The genomic spectrum of rhabdomyosarcoma (RMS) progression from primary to relapse is not fully understood. In this study we investigate 35 patients with relapsed RMS from two contributing institutions, 18 fusion-positive (FP-RMS) and 17 fusion-negative RMS (FN-RMS). Targeted DNA or whole exome sequencing (WES) was used to detect alterations in paired primary/relapsed samples. In 10 cases, circulating tumor DNA (ctDNA) from multiple timepoints through clinical care and progression was analyzed for feasibility of liquid biopsy in monitoring treatment response/relapse. ctDNA alterations were evaluated using a targeted custom RMS panel (36 genes) at high coverage for single nucleotide variation and fusion detection, and a shallow whole genome sequencing for copy number variation. FP-RMS had a stable genome with relapse, with the most common secondary alterations : CDKN2A/B, MYCN and CDK4 alterations, being already present at diagnosis and impacting overall survival. FP-RMS lacking major secondary events at baseline acquired recurrent MYCN and AKT1 alterations. FN-RMS acquired a higher number of new alterations, most commonly SMARCA2 missense mutations. ctDNA analyses detected pathognomonic variants in all RMS patients at diagnosis, regardless of FP/FN or type of alterations, while at relapse selected alterations were confirmed in 86% of FP-RMS and 100% FN-RMS. Moreover, a higher number of fusion reads was detected with increased disease burden and at relapse in patients following a fatal outcome. These results underscore patterns of tumor progression within a relatively stable genomic landscape and provide rationale for using liquid biopsy to monitor treatment response.

Study EGAS00001007399

Cohesin Mutations in AML

Cohesin shapes the nuclear chromatin architecture, including enhancer-promoter interactions, and its components, of which especially STAG2 and RAD21, are frequently mutated in myeloid malignancies. To elucidate mechanisms of leukemogenesis associated with cohesin mutations in humans, we comprehensively characterized genetic, epigenetic, transcriptional, and chromatin conformational changes in acute myeloid leukemia (AML). To corroborate our findings, we performed complementary siRNA-mediated depletion of STAG2, its paralogue STAG1 or RAD21 in cord blood-derived CD34+ primary human hematopoietic stem and progenitor cells (HSPCs). We show that STAG2 mutations consistently lead to the loss of STAG2 protein and are associated with a specific set of co-occurring mutations, while STAG1 was never mutated in AML. Loss of STAG2 was frequently compensated by STAG1. Still, specific loci displayed altered cohesin occupancy, gene expression and corresponding changes in local chromatin activation as measured by H3K27ac enrichment and chromatin accessibility. High-throughput chromosome conformation capture (in-situ Hi-C) revealed significantly altered chromatin looping in cohesin-mutated AMLs, including weakened enhancer-promoter contacts with reduced, cohesin-dependent promoter activity. In HSPCs, we detected transcriptomic and epigenetic effects overlapping STAG2-mutant AML-specific changes following STAG2 knockdown (KD), that were not invoked by the depletion of STAG1. We also found that STAG2 loss in cultured HSPCs impaired the differentiation capacity, especially erythroid colony formation which maintained HSPC-like gene expression. This work establishes STAG2 as a key regulator of cohesin-associated chromatin architecture, gene expression and differentiation in the human hematopoietic system and identifies candidate target genes that may be implicated in leukemogenesis.

Study EGAS00001007405

Clinical and genetic factors associated with tumor response to neoadjuvant (chemo)radiotherapy, survival and recurrence risk in rectal cancer

Rectal cancer poses challenges in preoperative treatment response, with up to 30% achieving a complete response (CR). Personalized treatment relies on accurate identification of responders at diagnosis. This study aimed to unravel CR determinants, overall survival (OS), and time to recurrence (TTR) using clinical and targeted sequencing data. Analyzing 402 patients undergoing preoperative treatment, tumor stage, size, and treatment emerged as robust response predictors. CR rates were higher in smaller, early-stage, and intensively treated tumors. Targeted sequencing analyzed 216 cases, while 120 patients provided hotspot mutation data. KRAS mutation dramatically reduced CR odds by over 50% (odds ratio [OR]=0.3 in the targeted sequencing and OR=0.4 hotspot cohorts, respectively). In contrast, SMAD4 and SYNE1 mutations were associated with higher CR rates (OR=6.0 and 6.8, respectively). Favorable OS was linked to younger age, CR, and low baseline carcinoembryonic antigen levels. Notably, CR and an APC mutation increased TTR, while a BRAF mutation negatively affected TTR. Beyond tumor burden, SMAD4 and SYNE1 mutations significantly influenced CR. KRAS mutations independently correlated with radiotherapy resistance, and BRAF mutations heightened recurrence risk. Intriguingly, nonresponding tumors with initially small sizes carried a higher risk of recurrence. These findings offer insights into rectal cancer treatment response, guiding personalized therapeutic strategies. By uncovering factors impacting CR, OS, and TTR, this study underscores the importance of tailored approaches for rectal cancer patients. These findings, based on extensive analysis and mutation data, pave the way for personalized interventions, optimizing outcomes in the challenges of rectal cancer preoperative treatment.

Study EGAS00001007501

Peripheral blood DNA methylome in adalimumab-treated patients with rheumatoid arthritis

Background and aims Rheumatoid arthritis (RA) patients are currently treated with biological agents mostly aimed at cytokine blockade such as anti-TNFα therapy. Currently, there are no biomarkers to predict therapy response to these agents. Here, we aimed to predict response to adalimumab (ADA) treatment in RA patients using DNA methylation in peripheral blood Methods DNA methylation profiling on whole peripheral blood from 92 RA patients before the start of adalimumab (ADA) was determined using Illumina HumanMethylationEPIC BeadChip Array. After 6 months, treatment response was assessed according to the Alliance of Associations for Rheumatology (EULAR) criteria for disease response. Patients were classified as responders (DAS28<3.2 or decrease of 1.2 points) or as non-responders (DAS28>5.1 or decrease of less than 0.6 points). Machine learning models were built with gradient boosting and stability selection models to predict response prior to ADA treatment with predictor DNA methylation markers. Results We demonstrated a 27-feature panel of DNA methylation markers or CpG classifiers that predict response in RA patients treated with ADA. Forty-nine patients were assigned as responder and 43 patients assigned as non-responders. We differentiate responders from non-responders with a high sensitivity (AUC 0.76). The predictor CpGs annotated to genes involved in immunological- and pathophysiological pathways related to RA such as T-cell signaling, B-cell pathology and angiogenesis. Conclusion Our findings indicate that DNA methylation signatures discriminate responders and non-responders to ADA treatment and can serve as a tool for therapy prediction.

Study EGAS00001007578

Evaluation of EBUS-TBNA Aspirates from Advanced NSCLC for Comprehensive Sequencing Platforms Including Whole Genome Sequencing

Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is often the only source of tumor tissue from patients with advanced, inoperable lung cancer. EBUS-TBNA aspirates are used for the diagnosis, staging, and genomic testing to inform therapy options. Here we extracted DNA and RNA from 220 EBUS-TBNA aspirates to evaluate their suitability for whole genome (WGS), whole exome (WES), and comprehensive panel sequencing. For a subset of 40 cases, the same nucleic acid extraction was sequenced using WGS, WES, and the TruSight Oncology 500 assay. Genomic features were compared between sequencing platforms and compared with those reported by clinical testing. A total of 204 aspirates (92.7%) had sufficient DNA (100 ng) for comprehensive panel sequencing, and 109 aspirates (49.5%) had sufficient material for WGS. Comprehensive sequencing platforms detected all seven clinically reported tier 1 actionable mutations, an additional three (7%) tier 1 mutations, six (15%) tier 2–3 mutations, and biomarkers of potential immunotherapy benefit (tumor mutation burden and microsatellite instability). As expected, WGS was more suited for the detection and discovery of emerging novel biomarkers of treatment response. WGS could be performed in half of all EBUS-TBNA aspirates, which points to the enormous potential of EBUS-TBNA as source material for large, well-curated discovery-based studies for novel and more effective predictors of treatment response. Comprehensive panel sequencing is possible in the vast majority of fresh EBUS-TBNA aspirates and enhances the detection of actionable mutations over current clinical testing.

Study EGAS00001007708

RNA isoform repertoire of neuropsychiatric risk genes in human brain

Neuropsychiatric disorders are highly complex conditions and the risk of developing a disorder has been tied to hundreds of genomic variants that alter the expression and/or products (isoforms) made by risk genes. However, how these genes contribute to disease risk and onset through altered expression and RNA splicing is not well understood. Here we show our current understanding of gene isoforms is far from complete and reveal the precise splicing profiles of neuropsychiatric disorder risk genes. Combining our new bioinformatic pipeline IsoLamp with nanopore long-read amplicon sequencing, we deeply profiled the RNA isoform repertoire of 31 high-confidence neuropsychiatric disorder risk genes in human brain. We show most risk genes are more complex than previously reported, identifying 443 novel isoforms and 28 novel exons, including isoforms which alter protein domains, and genes such as ATG13 and GATAD2A where most expression was from previously undiscovered isoforms. The greatest isoform diversity was present in the schizophrenia risk gene ITIH4. Mass spectrometry of brain protein isolates confirmed translation of a novel exon skipping event in ITIH4, suggesting a new regulatory mechanism for this gene in brain. Our results emphasize the widespread presence of previously undetected RNA and protein isoforms in brain and provide an effective approach to address this knowledge gap. Uncovering the isoform repertoire of neuropsychiatric risk genes will underpin future analyses of the functional impact these isoforms have on neuropsychiatric disorders, enabling the translation of genomic findings into a pathophysiological understanding of disease.

Study EGAS00001007744

Pharmacogenomic Analysis Reveals New Therapeutic Options for Pleural Mesothelioma

Background: Pleural mesothelioma (PM) urgently requires novel effective treatments. Drug repurposing is a relevant strategy to discover new therapeutic options among well-known drugs used in clinical practice. This study aimed to identify new therapies in the context of molecular heterogeneity of PM. Methods: We performed a multi-omics study of the largest cohort of patient-derived primary PM cell lines (n=58) to date, using whole exome sequencing, RNA sequencing and methylome analysis. We also conducted a large-scale drug screening of over 1300 compounds on a subset of cell lines (n=11), as well as an extension screen (n=48) for selected drugs of interest. The best candidates were validated using 3D culture and mouse models. Results: We demonstrated that the molecular landscape of the cell lines cohort recapitulates the main findings in tumours and revealed new specific features of PM. The large-scale drug screening and subsequent validations highlighted notably strong sensitivity to entinostat and fluvastatin. Importantly, both compounds displayed same efficacy in 2D and 3D culture models and single treatment prolonged survival in vivo similarly or even better than standard chemotherapy. Strikingly, combining entinostat treatment with anti-PD1 led to cures in some mice and immunized them against tumour cells. Conclusions: Among several candidates, we identified entinostat, notably in combination with immune checkpoint inhibitor, and to a lesser extent fluvastatin, as promising therapeutic options for patients. We believe our study provides a valuable resource that could contribute to advances in the field and warrants further clinical investigation.

Study EGAS00001007866

The University of Hong Kong Intestinal Metaplasia Organoids Study

Background: Gastric intestinal metaplasia (IM) is a pre-cancerous stage spanning a morphological spectrum that is poorly represented by human cell line models. Objective: We aim to establish and characterize human IM cell models to better understand IM progression along the cancer spectrum. Design: A large human gastric IM organoid (IMO) cohort (n=28), their clonal derivatives and normal gastric organoids (n=42) for comparison were established. Comprehensive multi-omics profiling and functional characterization were performed. Results: Single-cell transcriptomes revealed IMO cells spanning a spectrum from hybrid gastric/intestinal to advanced intestinal differentiation. Their lineage trajectories connected different cycling and quiescent stem and progenitors, highlighting differences in gastric to IM transition and the potential origin of IM from STMN1 cycling isthmus stem cells. Hybrid IMOs showed impaired differentiation potential, high lineage plasticity beyond gastric or intestinal fates, and reactivation of a fetal gene program. Cell populations in gastric IM and cancer tissues were highly similar to those derived from IMOs and exhibited a fetal signature. Genomically, IMOs showed elevated mutation burden, frequent chromosome 20 gain, and epigenetic de-regulation of many intestinal and gastric genes. Functionally, IMOs were FGF10 independent and showed downregulated FGFR2. Several IMOs exhibited a cell-matrix adhesion independent (CMi) subpopulation that displayed chromosome 20 gain but lacked key cancer driver mutations, potentially representing the earliest neoplastic precursor of IM-induced gastric cancer. Conclusions: Overall, our IM organoid biobank captured the heterogeneous nature of IM, revealing mechanistic insights on IM pathogenesis and progression, offering an ideal platform for studying early gastric neoplastic transformation and chemoprevention.

Study EGAS00001007899

OMKar

The whole genome karyotype refers to the sequence of large chromosomal segments that make up an individuals genotype. karyotype analysis, which includes descriptions of aneuploidies and other rearrangements is crucial for understanding genetic risk factors, for diagnosis, treatment decisions, and genetic counseling linked to constitutional disorders. The current karyotyping standard is based on microscopic examination of chromosomes, a complex process that requires high expertise and offers Mb scale resolution. Optical Genome Mapping (OGM) technology can identify large DNA lesions in a cost-effective manner. In this paper, we developed OMKar, a method that uses OGM data to create a virtual karyotype. OMKar processes Structural (SV) and Copy Number (CN) Variants as inputs and encodes them into a compact breakpoint graph. It recomputes copy numbers using Integer Linear Programming to maintain CN balance and then identifies constrained Eulerian paths representing entire donor chromosomes. In tests using 38 whole genome simulations of constitutional disorders, OMKar reconstructed the karyotype with 88% precision and 95% recall on SV concordance and 95% Jaccard score on CN concordance. We applied OMKar to 50 prenatal, 41 postnatal, and 63 parental samples from ten different sites. OMKar reconstructed the correct karyotype in 144 out of 154 samples, covering 25 of 25 aneuploidies, 32 of 32 balanced translocations, and 72 of 82 unbalanced variations. Detected constitutional disorders included Cri-du-chat, Wolf-Hirschhorn, Prader-Willi deletions, Down, and Turner syndromes. Importantly, it identified a plausible genetic mechanism for five cases of constitutional disorder that were not detected by other technologies. Together, these results demonstrate the robustness of OMKar for OGM-based karyotyping.

Study EGAS00001008245

Clinical relevance of somatic copy-number alterations in plasma circulating tumor DNA from advanced EGFR-mutated NSCLC patients treated with osimertinib

Background: Somatic copy-number alterations (SCNAs) are associated with drug resistance in patients with advanced epidermal growth factor receptor (EGFR)-mutated non-small cell lung cancer (NSCLC) treated with EGFR-tyrosine kinase inhibitors (TKIs). The purpose of our study was to assess the clinical relevance and development of genome-wide SCNAs in plasma circulating tumor DNA (ctDNA) under osimertinib therapy.Methods: We included 43 patients with advanced EGFR T790M-positive lung adenocarcinoma who were treated with osimertinib after progression under previous EGFR-TKI therapy. We performed genomic profiling of ctDNA in plasma samples from each patient obtained pre-osimertinib and after patients developed resistance to osimertinib. SCNAs were detected by shallow whole-genome plasma sequencing and EGFR mutations were assessed by droplet digital PCR.Results: SCNAs in resistance-related genes (rrSCNAs) were detected in 10 out of 39 (25.6%) evaluable patients before start of osimertinib. The presence of rrSCNAs in plasma before initiation of osimertinib therapy was associated with a lower response rate to osimertinib (50% versus 86%, p=0.02) and was an independent predictor for shorter progression-free survival (adjusted HR 3.26, 95% CI 1.37-7.75, p=0.008) and overall survival (adjusted HR 2.41, 95% CI 1.09-5.34, p=0.03).Conclusions: Genomic profiling of plasma ctDNA is clinically relevant and affects the efficacy and clinical outcome of osimertinib. Our approach allows comprehensive assessment of SCNAs in plasma samples of lung adenocarcinoma patients and may help to guide genotype-specific therapeutic strategies in the future.

Study EGAS00001004539

Combination of ribociclib and gemcitabine for the treatment of medulloblastoma

Group 3 (G3) medulloblastoma (MB) is one of the deadliest forms of the disease for which novel treatment is desperately needed. Here we evaluate ribociclib, a highly selective CDK4/6 inhibitor, with gemcitabine in mouse and human G3 MBs. Ribociclib CNS penetration was assessed by in vivo microdialysis and by immunohistochemistry and gene expression studies. Survival studies to determine the efficacy of ribociclib and gemcitabine combination were performed on mice orthotopically implanted with luciferase labelled mouse and human G3 MB. Pharmacokinetic-pharmacodynamic outcomes and univariable survival models were analyzed to estimate survival. Gene activity inference using NetBID and tumor differentiation analysis investigated the effects of the combination after short and long-term treatments. Tumors from mice treated with oral ribociclib displayed inhibited RB phosphorylation, downregulated E2F target genes, and decreased proliferation. Treatment of mice with the combination of ribociclib and gemcitabine was well tolerated, slowed tumor progression and metastatic spread, and increased survival. Molecular analysis of treated versus untreated tumors showed a significant decrease in the activity and expression of genes involved in cell cycle progression and DNA damage response, and an increase in activity and expression of genes implicated in neuronal identity and neuronal differentiation. Ribociclib is CNS-penetrant. When administered/combined with gemcitabine in orthotopic G3 MB models resulted in improved survival. Our findings, with both mouse and human patient-derived-orthotopic xenograft models, suggest that this combination therapy has promise for children with G3 MB and may represent an effective treatment strategy for other CNS malignancies.

Study EGAS00001006001

Implementation of pediatric precision oncology into clinical practice: The individualized Therapies for Children with cancer program “iTHER”

iTHER is a prospective national precision oncology program aiming to define tumor molecular profiles in children and adolescents with primary very high-risk, relapsed, or refractory pediatric tumors in order to identify relevant aberrations to inform treatment. From April 2017 to April 2021, 302 samples of 253 patients were included. Comprehensive molecular profiling utilizing lcWGS, WES, RNAseq, Affymetrix, and/or 850k methylation profiling was performed for 226 samples. Germline pathogenic variants were identified in 16% of patients. At least one somatic alteration was detected in 204 (90.3%), and 185 (81.9%) were considered druggable, with priority levels very high (6.1%), high (21.3%), moderate (26.0%), intermediate (36.1%), and borderline (10.5%). Diagnosis was revised or refined in 8 patients (3.5%). Spatial and temporal heterogeneity was observed in paired samples of 15 patients, indicating the value of sequential analysis. Of 137 patients with follow-up beyond 12 months, 21 molecularly matched treatments were applied in 19 patients (13.9%) with modest response. Most relevant barriers to not applying targeted therapies included poor performance status, as well as limited access to drugs within clinical trial. iTHER demonstrates feasibility of comprehensive molecular profiling across all ages, tumor types and stages in pediatric cancers, informing of diagnostic, prognostic, and targetable alterations as well as reportable germline variants within a clinically relevant timeframe. Therefore, WES and RNAseq is implemented into standard clinical care at the Princess Máxima Center for all children. Improved access to targeted treatments within biology-driven combination trials is required to eventually improve survival.

Study EGAS00001007099

Whole_genome_sequencing_of_100_DDD_trios_with_suspected_noncoding_causal_mutations

We would like to whole-genome sequence 100 trios (300 individuals) from the DDD project in which we suspect the proband has a pathogenic noncoding mutation, to 30X coverage. These have been carefully selected to maximise the chances of finding pathogenic noncoding mutations. Specifically, we have selected probands who have no likely causal mutation within the coding region but who have a heterozygous loss-of-function mutation inherited from one parent in a known recessive developmental disorder gene, and whose phenotype is a good match for the typical phenotype caused by recessive variants in that gene. We suspect that these probands may have a heterozygous noncoding mutation on the other allele which reduces expression of the gene so that, together, these two mutations are effectively equivalent to a homozygous loss-of-function mutation. About a quarter of the probands have affected siblings and, if those siblings have been exome sequenced, we have checked that they are identical-by-descent in the region of the gene. We propose to search in the promoter region, intronic and annotated regulatory regions around these genes of interest for rare variants inherited from the other parent (i.e. not the one who transmitted the loss-of-function variant), or de novo variants. If we find such variants, and demonstrate an enrichment of this compound heterozygous LoF noncoding mechanism above that expected by chance, we intend to follow up specific candidates by RNAseq and potentially CRISPR/Cas9 experiments. 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 please see http://www.sanger.ac.uk/datasharing/

Study EGAS00001002452

A proof-of-concept study of sequential treatment with the HDAC inhibitor vorinostat following BRAF and MEK inhibitors in BRAFV600 mutated melanoma

"Purpose: Development of resistance limits the clinical benefit of BRAF and MEK inhibitors (BRAFi/MEKi) in BRAFV600 mutated melanoma. It has been shown that short-term treatment (14 days) with vorinostat was able to initiate apoptosis of the resistant tumor cells. We aimed to assess the anti-tumor activity of sequential treatment with vorinostat following BRAFi/MEKi in patients with BRAFV600 melanoma who progressed after initial response to BRAFi/MEKi. Patients and Methods: Patients with BRAFi/MEKi resistant BRAFV600 melanoma were treated with vorinostat 360 mg QD for 14 days followed by BRAFi/MEKi. The primary endpoint was an objective response rate of progressive lesions of at least 30% according to RECIST 1.1. Secondary endpoints included progression-free survival (PFS), overall survival (OS), safety, pharmacokinetics of vorinostat and translational molecular analyses using ctDNA and tumor biopsies. Results: Twenty-six patients with progressive BRAFi/MEKi resistant BRAFV600 mutated melanoma received treatment with vorinostat. Twenty-two patients were evaluable for response. The ORR was 9% (one complete response for 31.2 months and one partial response for 14.9 months. Median PFS and OS were 1.4 and 5.4 months, respectively. Common adverse events were fatigue (23%) and nausea (19%). ctDNA analysis showed emerging secondary mutations in NRAS and MEK in eight patients at time of BRAFi/MEKi resistance. Elimination of these mutations by vorinostat treatment was observed in three patients. Conclusions: Intermittent treatment with vorinostat in patients with resistant BRAFV600 mutated melanoma is well tolerated. Although the primary endpoint of this study was not met, durable anti-tumor responses were observed in a minority of patients (9%). "

Study EGAS00001007709

Toxigenic Clostridium perfringens isolated from at-risk pediatric inflammatory bowel disease patients

With the goal of studying mucosal-associated bacteria and products detrimental to inflammatory bowel disease (IBD) patients, we directly cultured bacterial communities from mucosal biopsies and examined for detrimental traits. Focusing on red blood cell lysis, a virulence trait, communities from 5 of 9 patients exhibited hemolytic activity. Clostridium perfringens was isolated from each hemolytic community, and whole-genome sequencing confirmed presence of hemolytic toxins – alpha toxin in all 5 strains, perfringolysin O (PFO) in 4 strains, alveolysin in 2 strains – and absence of enterotoxins. In vitro cytotoxicity experiments demonstrated strain supernatants were toxic to various cell types located beneath the intestinal epithelial barrier, including endothelial, neuroblasts, and neutrophils, while impact on epithelial cells was less pronounced. These findings suggest C. perfringens may be damaging particularly when intestinal barrier integrity is compromised, such as in IBD patients. Further characterization using purified toxins and genetic insertion mutants confirmed PFO toxin was sufficient for cell toxicity. C. perfringens supernatants also induced activation of neuroblast and dorsal root ganglion (DRG) neuron cells in vitro, suggesting C. perfringens in inflamed mucosal tissue may directly contribute to abdominal pain, a frequent IBD symptom. Strikingly, C. perfringens was detected in biopsies of 8 of 9 pediatric patients while not in all corresponding stool samples, and in other datasets, C. perfringens was in stool samples of IBD adults (18.7-27.1%) much more frequently versus healthy (5.1%). Our findings showcase C. perfringens may have an important pathogenic impact on IBD patients. Similar to Clostridioides difficile, routine monitoring of C. perfringens and PFO toxins in patients may be beneficial.

Study EGAS50000000334

METABRIC

Solid tumors are complex tissues composed of a mixture of cancer and normal cells, which complicates the interpretation of their molecular profiles. Normal cell contamination can dilute cancer cell information and tissue architecture is generally not reflected in molecular assays. To address these challenges, we developed a computational approach based on standard Haematoxylin and Eosin-stained sections and demonstrated its power in a discovery cohort of 323 breast tumors and an independent validation cohort of 241 tumors. First, to deconvolute cellular heterogeneity and detect subtle genomic aberrations, we introduced an algorithm based on tumor cellularity to increase the comparability of copy-number profiles between samples. Second, we demonstrated that a predictor for survival integrating image-based and molecular features significantly outperforms classifiers based on single data types. Third, we described and validated a novel, independent prognostic factor based on quantitative analysis of spatial patterns between stromal cells, which are not detectable by molecular assays. Our quantitative methods refine and complement molecular assays of tumor samples and could benefit all large-scale cancer studies.First, to deconvolute cellular heterogeneity and detect subtle genomic aberrations, we introduced an algorithm based on tumor cellularity to increase the comparability of copy-number profiles between samples. Second, we demonstrated that a predictor for survival integrating image-based and molecular features significantly outperforms classifiers based on single data types. Third, we described and validated a novel, independent prognostic factor based on quantitative analysis of spatial patterns between stromal cells, which are not detectable by molecular assays. Our quantitative methods refine and complement molecular assays of tumor samples and could benefit all large-scale cancer studies.

Study EGAS00000000098

Cell-Free DNA Genomic and Fragmentomic Features for Early Outcome Prediction in Diffuse Large B-Cell Lymphoma

Purpose: Diffuse large B-cell lymphoma (DLBCL) patients need an accurate and early risk stratification strategy as prompt therapy escalation may improve outcome. Patients and methods: We evaluated cell free DNA (cfDNA) genomic and fragmentomic features in 190 patients with large B-cell lymphoma from more than 40 hospitals in the Benelux using Whole Genome Sequencing (WGS). We defined a new metric called ACT score (Aberrations, Contribution of short fragments, Terminal motif analyses) by combining four cfDNA signals and evaluated its performance to predict end-of-treatment (EOT) response and survival. Results: Individual cfDNA features and ACT score were altered per EOT response after one cycle of treatment (T1). The ACT score at T1 outperformed all individual cfDNA features in predicting EOT response (AUC = 0.74). Patients with a positive ACT score had an inferior outcome compared to ACT score negative patients [progression-free survival (PFS): HR 5.0 (95% CI 3.1-8.2), log-rank test, p < 0.0001) and overall survival (OS): HR 6.5 (95% CI 3.5-12.2), log-rank test, p < 0.0001]. The 2-year PFS in ACT score positive and negative patients were 29.8% and 78.1%, respectively. The prognostic value of the ACT score is independent of the International Prognostic Index and interim imaging. Conclusions: ACT score computed from a single plasma sample collected after one cycle of treatment can predict clinical outcome. This low-cost and easy-to-interpret test does not require tissue biopsies or a priori knowledge of mutations and has the potential to aid patient selection in interventional clinical trials and risk-adapted treatment strategies.

Study EGAS50000000412

Phase 1/2 Study of the Indoleamine 2,3-Dioxygenase 1 Inhibitor Linrodostat Mesylate Combined With Nivolumab or Nivolumab and Ipilimumab in Advanced Solid Tumors or Hematologic Malignancies

Purpose: To evaluate the safety, efficacy, pharmacokinetics, pharmacodynamics, and biomarker data of linrodostat mesylate, a selective, oral indoleamine 2,3-dioxygenase 1 (IDO1) inhibitor, combined with nivolumab ± ipilimumab in advanced solid tumors and hematologic malignancies. Patients and Methods: In this phase 1/2 study, patients received once-daily (QD) linrodostat (part 1 [escalation], 25-400 mg; part 2 [expansion], 100 or 200 mg) plus nivolumab (480 mg every [Q] 4 weeks [W] or 240 mg Q2W) or triplet therapy (part 3, linrodostat 20-100 mg QD; nivolumab 360 mg Q3W or 480 mg Q4W; ipilimumab 1 mg/kg Q6W or Q8W). Endpoints included safety and efficacy (co-primary; parts 2, 3), pharmacokinetics, pharmacodynamics, biomarkers, and efficacy (part 1). Results: Fifty-five, 494, and 41 patients were enrolled in parts 1, 2, and 3, respectively. Linrodostat exposures exceeded predicted therapeutic target concentrations starting at 50 mg. Rates of grade 3/4 adverse events were 50.1%-63.4%. The maximum tolerated linrodostat dose was 200 mg; dose-limiting toxicities were primarily immune related. Responses were observed across different cohorts, study parts, and tumor types, particularly in immunotherapy-naive patients. Kynurenine decreased with linrodostat + nivolumab, regardless of response. In contrast, interferon gamma (IFN-γ) gene expression signature was associated with response; in nonmelanoma patients, a composite of low tryptophan 2,3-dioxygenase (TDO2) gene expression plus high IFN-γ signature was associated with response. Conclusions: Linrodostat + nivolumab ± ipilimumab demonstrated a manageable safety profile. Kynurenine changes supported IDO1 pathway inhibition but did not correlate with response. A composite biomarker of low TDO2 expression plus high IFN-γ gene expression may predict response to linrodostat + nivolumab.

Study EGAS50000000710

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