Search Results - EGA European Genome-Phenome Archive

Liquid biopsy-based minimal residual disease monitoring for early risk stratification and decision-making in advanced non-small cell lung cancer

Circulating tumor DNA (ctDNA)-based minimal residual disease (MRD) monitoring shows promise for risk stratification and decision-making in cancer patients. However, factors like background noise from non-tumor DNA, clonal haematopoiesis, and non-shedding tumors may complicate manual interpretation and limit its clinical application. In this proof-of-concept study in advanced non-small cell lung cancer (NSCLC) patients treated with immune checkpoint inhibitors (ICIs), we developed an algorithm that automatically classifies serial cell-free DNA (cfDNA) samples, thereby enabling reliable and reproducible interpretation, and preventing time-consuming manual interpretation in approximately 75% of patients. Importantly, application of the algorithm allowed early risk stratification and decision-making, specifically identifying approximately 35% of patients with short-term clinical benefit and approximately 25% of patients who may potentially benefit from treatment escalation. Simultaneous serum tumor marker (STM) monitoring further improved risk stratification and decision-making in our study, enabling accurate identification of all patients with a clinical benefit of at least one year.

Study EGAS50000001554

HIV-phyloTSI: Subtype-independent estimation of time since HIV-1 infection for cross-sectional measures of population incidence using deep sequence data

Estimating the time since HIV infection (TSI) at population level is essential for tracking changes in the global HIV epidemic. Most methods for determining TSI give a binary classification of infections as recent or non-recent within a window of several months, and cannot assess the cumulative impact of an intervention. We developed a Random Forest Regression model, HIV-phyloTSI, which combines measures of within-host diversity and divergence to generate continuous TSI estimates directly from viral deep-sequencing data, with no need for additional variables. HIV-phyloTSI provides a continuous measure of TSI up to 9 years, with a mean absolute error of less than 12 months overall and less than 5 months for infections with a TSI of up to a year. It performs equally well for all major HIV subtypes based on data from African and European cohorts. We demonstrate how HIV-phyloTSI can be used for incidence estimates on a population level.

Study EGAS50000000895

Targeted sequencing (paired) of HR genes in primary and metastatic patient-derived xenografts (PDXs) of colorectal cancer (CRC)

Chemotherapy is the standard-of-care treatment for metastatic colorectal cancer (mCRC) and benefits some patients, but what distinguishes responders from non-responders is unclear. In this study, we leveraged a comprehensive collection of 69 molecularly annotated patient-derived xenografts to uncover functional predictors of response to 5-FU and irinotecan combination therapy (FOLFIRI) in mCRC. Genetic analyses revealed that treatment sensitivity was marked by genomic scars indicative of BRCAness, suggesting homologous recombination (HR) deficiency as a key determinant. Accordingly, we surveyed a manually curated panel of 44 genes with a documented role in HR for the potential presence of pathogenic mutations. We did not observe a specific enrichment of HR gene mutations based on response to FOLFIRI. This result, combined with the absence of widespread biallelic inactivation of the analyzed genes and the predominance of mutations categorized as variants of unknown significance, suggests that FOLFIRI sensitivity is not primarily governed by underlying mutations in HR genes responsible for mitigating the genotoxic effects of this therapeutic regimen.

Study EGAS50000000075

Shallow Whole Genome Sequencing of Patient Derived Xenografts

Chemotherapy is the standard-of-care treatment for metastatic colorectal cancer (mCRC) and benefits some patients, but what distinguishes responders from non-responders is unclear. In this study, we leveraged a comprehensive collection of 27 molecularly annotated patient-derived xenografts to uncover functional predictors of response to 5-FU and irinotecan combination therapy (FOLFIRI) in mCRC. Genetic analyses revealed that treatment sensitivity was marked by genomic scars indicative of BRCAness, suggesting homologous recombination (HR) deficiency as a key determinant. Accordingly, we surveyed a manually curated panel of 44 genes with a documented role in HR for the potential presence of pathogenic mutations. We did not observe a specific enrichment of HR gene mutations based on response to FOLFIRI. This result, combined with the absence of widespread biallelic inactivation of the analyzed genes and the predominance of mutations categorized as variants of unknown significance, suggests that FOLFIRI sensitivity is not primarily governed by underlying mutations in HR genes responsible for mitigating the genotoxic effects of this therapeutic regimen.

Study EGAS50000000191

Hyperdiploidy impairs fetal hematopoietic progenitor cell fitness and differentiation enabling persistence of rare preleukemic aneuploid clones

Cells previously cryopreserved in FBS-10%DMSO were thawed and resuspended in 1mL of cold lysis buffer (10 mM Tris-HCl pH 7.4, 154 mM NaCl, 0.2% BSA, 0.1% NP-40, 1 mM CaCl₂, 0.5 mM MgCl₂ in ultra-pure water) to lyse the cell membrane and release intact nuclei. The nuclei were stained with propidium iodide (10 µg/mL) and Hoechst 33258 (10µg/mL) to facilitate sorting based on cell cycle state and viability. Single nuclei from 48 cells per sample were isolated into 96-well plates containing 5µL of freeze buffer (1X PBS, 7.5% DMSO, and 40% ProFreeze freezing medium (Lonza)) using a MoFlo Astrios cell sorter (Beckman Coulter) at the Flow Cytometry Unit of the University Medical Center Groningen (UMCG), Netherlands. The plates were centrifuged at 500 g and stored at -80°C until library preparation. Single-nuclei libraries were prepared using a Bravo Automated Liquid Handling Platform (Agilent Technologies). Nuclei were lysed, and DNA was labelled with unique 10 bp dual barcodes and amplified as previously described. Sequencing was performed on an Illumina NextSeq 2000 platform with 77bp single end reads. The generated data were subsequently demultiplexed using sample-specific barcodes and converted to FASTQ files with bcl2fastq. Sequencing reads were aligned to the GRCh38/hg38 human reference genome using Bowtie2 (v2.2.4), and duplicate reads were marked with BamUtil (v1.0.3). Single-cell karyotypes were determined by performing copy number analysis using AneuFinder (v4.3.3) (https://github.com/ataudt/aneufinder). The analysis included GC-content correction and blacklisting of artifact regions identified from euploid controls. Copy number calling was conducted with the dnacopy and edivisive algorithms, employing a bin size of 1 Mb and a step size of 500 Kb. Libraries with an average of fewer than 10 reads per chromosome copy per bin or less than 95% concordance between the two algorithms were excluded from analysis. Whole-chromosome aneuploidies were identified when over 95% of bins exhibited deviation from the disomic state. Aneuploidy scores were calculated as weighted averages of absolute copy number deviations from the euploid state.

Dataset EGAD50000002314

RTEL1 mutation as a modifier of Dyskeratosis Congenita in a family with a Telomerase RNA (hTR) template mutation and variant telomeric repeats

Vertebrate telomeres, the sequences protecting the end of linear chromosomes, are composed of conserved hexameric GGTTAG repeats. Here we present a C50>A telomerase RNA template mutation that results in the incorporation of the variant telomeric repeat GTTTAG in a family with dyskeratosis congenita primarily presenting as idiopathic pulmonary fibrosis. The mutant telomerase is characterized by decreased processivity in direct telomerase activity assays and in vivo based on data from Illumina next-generation whole genome sequencing and Oxford Nanopore Technologies long-read telomere sequencing. The latter provided positional mutant repeat information that revealed the inheritance and maintenance of proximal mutant repeats in individuals who did not inherit the template mutation. Additionally, we describe an RTEL1 nonsense mutation that is associated with very short telomeres in progeny harboring wild-type telomerase and inherited mutant telomeric repeats in the absence of overt clinical phenotypes. In contrast, co-inheritance of the RTEL1 nonsense and TERC r.C50>A mutations coincided with severe early-onset DC phenotypes in two individuals.

Study EGAS50000001644

Spatial predictors of response to immunotherapy in microsatellite stable metastatic colorectal cancer

Microsatellite stable (MSS) colorectal cancers (CRC) are largely unresponsive to immune checkpoint inhibition (ICI), prompting investigation into strategies to enhance sensitivity. The MAYA trial, which utilized temozolomide (TMZ) in MGMT-silenced MSS mCRC, hypothesized that TMZ-induced hypermutation could sensitize tumors to ICI. This phase II trial met its primary endpoint, demonstrating durable clinical responses with TMZ combined with ipilimumab and nivolumab. To elucidate factors influencing response heterogeneity, we conducted multi-omic spatial profiling of samples from patients who participated in the MAYA trial, including baseline and on-treatment tissue and blood specimens. While increased neoantigen load following TMZ exposure did not consistently predict for deep responses, spatial profiling revealed key determinants. Lymphocyte proportions, particularly CD8+KI67+ cells, within stromal and tumor compartments, along with macrophage composition (CD68+CD163+ cells) at the tumor-stromal interface, were predictive of response. Treatment pressures dynamically altered the tumor microenvironment composition and activated peripheral immune cells. This study is the first to identify spatial predictors of response to this promising novel treatment approach for MSS CRC.

Study EGAS50000001567

Fragmentomics Uncover Non-Mutational HRD Features

Homologous recombination deficiency (HRD) is a key biomarker in prostate cancer (PCa), predicting response to PARP inhibitors and platinum-based therapies. However, current diagnostics often rely solely on BRCA1/2 mutations or genomic scars, missing cases driven by other mechanisms. Tissue-based testing is further limited by tumor heterogeneity and biopsy challenges in metastatic bone disease. Here, we applied a comprehensive multimodal approach to assess HRD in 106 advanced PCa patients using circulating tumor DNA (ctDNA). This included targeted sequencing of homologous recombination repair (HRR) genes, low-pass WGS for genomic instability (sHRD), WES for mutational signatures, and cfDNA fragmentomics and chromatin accessibility profiling. BRCA2 was the most frequently altered gene, often co-occurring with PTEN loss. High sHRD scores correlated with BRCA2/RB1 loss, somatic copy number alterations, and poor survival. HRD tumors showed enrichment of SBS3/ID6 signatures, altered fragment lengths, and reduced accessibility at zinc finger transcription factor sites. These results support ctDNA-based multimodal profiling as a non-invasive strategy for HRD detection and stratification.

Study EGAS00001008190

Host factors dictate gut microbiome alterations in chronic kidney disease more strongly than to kidney function

Despite recent progress, microbial markers in Chronic Kidney Disease (CKD) remain inconclusive. We combined quantitative faecal metagenomics (N=130 CKD cohort) and cross-study biomarker comparisons (Ntotal=4420) to study microbiome associations with glomerular filtration rate (eGFR; kidney function) and 4-year CKD progression. Transit time (TT) and medications primarily explained microbiome variation, trumping eGFR-related effects. Metagenome analysis showed increased p-cresol and indole synthesis potential and decreased plant-to-animal CAZyme ratios with lower eGFR, coupled to a Bact1 to Rum enterotype shift, suggesting saccharolytic-to-proteolytic microbiome transitions linked to dietary guidelines and slowed-down TT. Peritoneal dialysis patients showed increased (dysbiotic) Bact2 prevalence and linked intestinal inflammation. Only Escherichia coli, an unnamed Alistipes species and Bifidobacterium adolescentis were confounder-independent markers for eGFR, but these nor previous markers convincingly replicated across 11 studies. No predictors for CKD progression were found. Together, poor evidence for microbiome biomarkers but substantial eGFR-independent effects were found, suggesting potential for nutritional and TT interventions in CKD.

Study EGAS50000000646

Distinct genomic profiles and clinical outcomes in constitutional mismatch repair deficiency-associated high-grade gliomas: insights into mutational signatures and clonal evolution

Constitutional mismatch repair deficiency (CMMRD) is a rare cancer-predisposition syndrome, yet the mutational processes and clonal evolution of CMMRD-associated high-grade gliomas (HGGs) remain incompletely understood. In this study, mutational signatures and tumor evolution were analyzed in 25 CMMRD-associated HGGs. Germline biallelic mutations were most frequently identified in MSH6 (56.0%), followed by PMS2 (36.0%) and MLH1 (8.0%). Affected patients showed very early disease onset (mean 5.8 years) and poor clinical outcomes, with a mean progression-free survival of 16 months. Distinct genomic and clinical differences were observed between MSH6- and PMS2-associated tumors. MSH6-deficient HGGs were enriched for SBS6, whereas PMS2-deficient tumors showed predominance of SBS21, and these mutational signatures were correlated with prognosis. Clonal evolution analyses revealed early involvement of POLE/POLD1 mutations and persistence of the founding clone at recurrence. Overall, the study highlights the importance of mutational signatures and clonal evolution in shaping tumor behavior and clinical outcomes in CMMRD-associated HGGs.

Study EGAS50000001506

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