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PubMed2026

Somatic mutations reveal hyperactive Notch signaling in prurigo nodularis.

Prurigo nodularis (PN) is a chronic inflammatory skin disease characterized by pruritic skin nodules of unknown etiology. Little is known about genetic changes in PN pathogenesis, particularly somatic events, which are often implicated in inflammatory conditions. We thus performed whole-exome sequencing on 54 lesional and nonlesional skin biopsies from 17 patients with PN and 10 patients with atopic dermatitis (AD) for comparison. Somatic mutational analysis revealed that PN lesional skin harbors recurrent somatic mutations in fibrotic, neurotropic, and cancer-associated genes that are absent in adjacent PN nonlesional skin. Nonsynonymous mutations were most frequently present in NOTCH1 and the Notch signaling pathway, a key regulator of cellular proliferation and tissue fibrosis. In contrast, NOTCH1 mutations were absent in AD. Somatic copy-number analysis, combined with expression data, identified recurrently deleted and downregulated genes in PN lesional skin, which are associated with axonal guidance and extension. Follow-up immunofluorescence validation demonstrated increased NOTCH1 expression in PN lesional skin fibroblasts and increased Notch signaling in PN lesional dermis. Finally, a multicenter analysis revealed increased risk of NOTCH1-associated diseases in patients with PN. In characterizing the somatic landscape of PN, this study highlights the potential role of Notch pathway dysregulation in PN pathogenesis and fibrosis.

Humans↗
PubMed2026

Optimizing GRIDSS for clinical use: A targeted NGS filtering strategy for germline structural variant detection.

Detecting intermediate-sized structural variants (SVs) remains challenging in diagnostics, as tools for single-nucleotide and copy-number variants, particularly read-depth-based methods, are often insufficient. GRIDSS addresses this gap by integrating paired-end mapping, split-read analysis, and assembly-based approaches. However, its use in targeted sequencing and diagnostic workflows remains complex. NGS panel data from 9726 patients with suspected hereditary cancer were analyzed using GRIDSS. A filtering strategy was developed to prioritize clinically relevant germline SVs. Multiple parameter settings were tested to optimize performance. The initial dataset of 1,307,592 variants was reduced to 89 candidates after applying the selected filtering strategy. Of these, 24 had been previously detected by routine callers and were not further analyzed. Among the remaining 65, 13 were considered likely true positives after visual inspection using IGV. Experimental validation was performed by Sanger/Nanopore long-read sequencing for these variants, all of which were confirmed. Eight were classified as (likely) pathogenic, including two frameshift duplications in MSH6, one splicing variant in BARD1, and five mobile element insertions in APC, BRCA2, and PALB2. Altogether, GRIDSS implementation increased diagnostic yield while maintaining feasibility for diagnostic workflows. Comprehensive workflow scheme for germline structural variant detection and results in our diagnostic setting.

Humans↗
PubMed2026

Association of FOXC1 Duplications With Juvenile Open-Angle Glaucoma.

IMPORTANCE: While FOXC1 single-nucleotide variants and deletions are well-established causes of Axenfeld-Rieger syndrome, few FOXC1 duplications have been reported. This study investigated families with duplications encompassing the FOXC1 gene to refine the associated phenotypic spectrum and contribution to glaucoma. OBJECTIVE: To investigate the prevalence and phenotype of FOXC1 duplications in 2 large glaucoma registries. DESIGN, SETTING, AND PARTICIPANTS: This retrospective observational genetic cohort study included participants recruited from the Australian & New Zealand Registry of Advanced Glaucoma (ANZRAG) and the Massachusetts Eye and Ear (MEE) cohort from 2008 through 2025. Participants with glaucoma, and available relatives, underwent genomic testing to identify duplications encompassing FOXC1 using exome sequencing and genotyping arrays (ANZRAG) or whole-genome sequencing (MEE). Data analyses were conducted from 2022 through 2025. MAIN OUTCOMES AND MEASURES: Prevalence of FOXC1 duplications, age at glaucoma onset, and phenotype, including ocular and systemic features. RESULTS: Twenty individuals from 10 families (50% female and 50% male; 70% self-described as broadly European [Australian/British, British, English/German, English/Polish, European, or Scottish], 25% as Asian [Chinese or Filipino], and 5% as Latin American [Salvadoran]) were identified with FOXC1 duplications. All genetically tested individuals were diagnosed with glaucoma, demonstrating high penetrance. Seventeen individuals were referred with juvenile open-angle glaucoma (JOAG), 1 with primary open-angle glaucoma, 1 with primary congenital glaucoma, and 1 with anterior segment dysgenesis. The diagnosis of 4 individuals from 1 family with ectropion uveae was revised to anterior segment dysgenesis. Systemic features were reported for 2 participants (10.5%), including subtle dental findings and mild facial dysmorphism. Duplications encompassing FOXC1 were among the most common monogenic contributors to JOAG. In the ANZRAG group, they accounted for 13.5% (95% CI, 6.7%-25.3%) of JOAG probands with a genetic diagnosis, second to MYOC (53.8%; 95% CI, 40.5%-66.7%). In the MEE group, FOXC1 duplications accounted for 9.5% (95% CI, 2.7%-28.9%) of JOAG probands with a genetic diagnosis. CONCLUSIONS AND RELEVANCE: These findings suggest FOXC1 duplications are an underrecognized, highly penetrant, but variably expressive, genetic variation associated with JOAG. Findings for the relatively modest number of individuals in the retrospective study were associated with wide confidence intervals. This limitation is often inherent to studies of JOAG, a rare condition for which individual genetic variants account for only a subset of cases. Despite this, the findings highlight the genetic heterogeneity of JOAG and support the potential importance of considering routine genetic copy-number variant analysis for individuals with JOAG.

Humans↗
PubMed2026

DNA Methylation Profiling of Pediatric Ectomesenchymoma Supports Embryonal Rhabdomyosarcoma-Like Epigenetic Identity.

Ectomesenchymoma is a rare, biphenotypic pediatric tumor combining rhabdomyoblastic and neuroectodermal differentiation. We characterize two novel cases through integrated genomics and the first report of genome-wide DNA methylation profiling. Both tumors harbored RAS-pathway mutations (HRAS p.Gly13Arg; NRAS p.Gln61His). Methylation analysis, including microdissected components, consistently aligned ectomesenchymoma with the embryonal rhabdomyosarcoma superfamily, revealing a shared myogenic epigenetic program despite neural differentiation. Shared copy-number profiles across distinct histological regions supported a monoclonal origin. Overall, our data support a close biological relationship between ectomesenchymoma and embryonal rhabdomyosarcoma and indicate that RAS-pathway testing and methylation profiling can significantly refine diagnostic precision.

Humans↗
PubMed2026

Clinical Utility of Trio Exome Sequencing in Rwandan Children With Autism Spectrum Disorder.

INTRODUCTION: Autism spectrum disorder (ASD) is a neurodevelopmental condition with substantial genetic and phenotypic heterogeneity. However, populations of African ancestry remain underrepresented in genomic studies, limiting understanding of ASD genetic architecture. This study aimed to characterize rare, clinically relevant genetic variants in a Rwandan pediatric ASD cohort using trio-based whole-exome sequencing (WES). METHODS: Trio-based WES was performed in 31 Rwandan pediatric patients with ASD (aged 2-18 years) and their parents. Variants were analyzed using a trio-based workflow and classified according to American College of Medical Genetics and Genomics/Association for Molecular Pathology (ACMG/AMP) guidelines. RESULTS: Eleven candidate variants were identified in 9 of 31 patients, including four likely pathogenic variants and seven variants of uncertain significance. This resulted in a diagnostic yield of 12.9% (4/31), expanded to 29.0% when phenotypically concordant variants of uncertain significance were considered. Most likely pathogenic variants were identified in individuals with syndromic ASD who presented with intellectual disability, epilepsy, and global developmental delay. Likely pathogenic findings included two single nucleotide variants in GABRB3, SYNGAP1, and two copy-number variants involving the GNAS locus and chromosome 1p35.3-p35.2. CONCLUSIONS: The diagnostic yield observed in this cohort is consistent with previous trio-based WES studies of ASD. The findings support the clinical utility of WES for the genetic evaluation of ASD and underscore the need for expanded genomic studies in African populations.

Humans↗
PubMed2026

Chromosome-scale genome remodeling in tumor evolution: Copy number alterations and structural variants as two sides of the same coin.

Chromosome-scale genomic rearrangements are a dominant force in tumor evolution. Copy-number alterations (CNAs) and structural variants (SVs) constitute two complementary axes of this process. Although detection technologies now deliver near-comprehensive catalogs, technical resolution has outpaced conceptual integration. In this review, we frame CNAs and SVs as inextricable facets of chromosomal aberrations. They reshape cancer genomes through altered gene dosage and three-dimensional regulatory rewiring. CNAs quantify the gene-dosage imbalance, yet arise through mechanistically distinct routes. Segmental CNAs typically require chromosomal breakage, and therefore often coincide with SV junctions. By contrast, whole-chromosome aneuploidy and whole-genome doubling (WGD) primarily reflect mitotic or cytokinetic failure and can occur without local breakpoints, while nevertheless reshaping the karyotypic landscape and seeding subsequent structural complexity. SVs, in turn, range from unbalanced events that alter copy number to ostensibly balanced exchanges that predominantly rewire regulatory architecture. Despite their diverse and sometimes catastrophic architectures, SVs are ultimately rooted in double-strand break formation and error-prone resolution. By integrating CNAs and SVs within a unified mechanistic and functional framework, we aim to convert catalogs into concepts and distill the organizing principles that govern tumor genome evolution.

Humans↗
PubMed2025

Assessment of the variant prioritization strategy for genomic newborn screening in the Generation Study.

PURPOSE: Genomic sequencing offers the opportunity to screen for hundreds of rare genetic conditions. To minimize potential negative impact on families and clinical services, it is crucial to reduce false-positive results while prioritizing clinical utility. We present an automated variant prioritization approach in the Generation Study, a research study investigating genomic sequencing in 100,000 newborns in England. Prioritized variants will subsequently undergo manual review by a registered clinical scientist and a specialist clinician before being reported back to parents. METHODS: We assessed specificity of our automated variant prioritization approach in 34,410 samples not enriched for rare diseases and sensitivity in 546 samples from patients with diagnostic variants in genes relevant to newborn screening. We used coverage and copy-number variants callability metrics to evaluate variant detection. RESULTS: We estimated that 3% to 5% of samples will have prioritized variants that require manual review and that <1% of cases will have reportable variants requiring further confirmation of the condition. Sensitivity in genes included in the Generation Study was estimated to be approximately 80%. Gene-level specificity results led to changes in variant prioritization rules and conditions that are included. CONCLUSION: Gene-specific assessment of variant prioritization is crucial to establish analytical validity prior to inclusion in genomic newborn screening.

Humans↗
PubMed2025

De novo rare EMX2 variants lead to idiopathic hypogonadotropic hypogonadism.

PURPOSE: The genetic etiology of infertility remains unknown. To identify genes for human infertility, we applied a de novo variant analysis in 142 parent-proband trios with idiopathic hypogonadotropic hypogonadism (IHH), an infertility disorder caused by gonadotropin-releasing hormone (GnRH) deficiency. METHODS: Rare de novo copy-number and single-nucleotide variants (CNVs and SNVs) were called from exome sequencing data of the IHH trios. An association study of common EMX2 variants and disease outcomes was performed in the Massachusetts General Brigham Biobank (N = 65,253). GnRH neuronal development and migration was studied in organotypic explants with knocked down of Emx2 and in a mouse model lacking Emx2. RESULTS: We identified that the gene EMX2 harbored both rare de novo CNVs and SNVs. Rare de novo EMX2 variants led to IHH, developmental delay, and hearing loss. Common EMX2 variants were linked to infertility, Parkinson disease, and hearing loss. Knockdown of Emx2 in nasal explants resulted in attenuated GnRH cell migration and GnRH cells were confined to nasal regions of Emx2 knockout (KO) mice, consistent with IHH pathogenesis. CONCLUSION: By utilizing a de novo variant analysis and cellular assays, EMX2 was uncovered as a gene for human infertility.

Humans↗
PubMed2003

Nuclear genetic control of mitochondrial DNA segregation.

Mammalian mitochondrial DNA (mtDNA) is a high copy-number, maternally inherited genome that codes for a small number of essential proteins involved in oxidative phosphorylation. Mutations in mtDNA are responsible for a broad spectrum of clinical disorders. The segregation pattern of pathogenic mtDNA mutants is an important determinant of the nature and severity of mitochondrial disease, but it varies with the specific mutation, cell type and nuclear background and generally does not correlate well with mitochondrial dysfunction. To identify nuclear genes that modify the segregation behavior of mtDNA, we used a heteroplasmic mouse model derived from two inbred strains (BALB/c and NZB; ref. 12), in which we had previously demonstrated tissue-specific and age-dependent directional selection for different mtDNA genotypes in the same mouse. Here we show that this phenotype segregates in F2 mice from a genetic cross (BALB/c x CAST/Ei) and that it maps to at least three quantitative-trait loci (QTLs). Genome-wide scans showed linkage of the trait to loci on Chromosomes 2, 5 and 6, accounting for 16-35% of the variance in the trait, depending on the tissue and age of the mouse. This is the first genetic evidence for nuclear control of mammalian mtDNA segregation.

Animals↗
PubMed2025

Molecular analysis of lung adenocarcinomas from the SAFIR02-Lung cohort reveals new metastasis-associated copy-number alterations including frequent mutant-specific KRAS-allelic imbalance and identifies CDKN2A homozygous deletions as an independent biomarker of poor prognosis.

BACKGROUND: Identifying molecular alterations specific to advanced lung adenocarcinomas could provide insights into tumour progression and dissemination mechanisms. METHOD: We analysed tumour samples, either from locoregional lesions or distant metastases, from patients with advanced lung adenocarcinoma from the SAFIR02-Lung trial by targeted sequencing of 45 cancer genes and comparative genomic hybridisation array and compared them to early tumours samples from The Cancer Genome Atlas. RESULTS: Differences in copy-number alterations frequencies suggest the involvement in tumour progression of LAMB3, TNN/KIAA0040/TNR, KRAS, DAB2, MYC, EPHA3 and VIPR2, and in metastatic dissemination of AREG, ZNF503, PAX8, MMP13, JAM3, and MTURN. Conversely, no meaningful difference was found in pathogenic single-nucleotide variant frequencies, reinforcing the notion that they are early events in tumorigenesis. CDKN2A homozygous deletion was linked to poor clinical outcome in patients with early tumours (overall survival hazard ratio 2.17, 95% CI: 1.43-3.28, corrected p-value&#x2009;=&#x2009;0.01). Furthermore, we found that KRAS mutant allele specific imbalance, i.e. focal amplification of the mutant allele, is more prevalent in locoregional or distant samples of metastatic patients than in early lesions (8.4%, 13% and 2.8% respectively). This observation was replicated in three public cohorts. Tumours with KRAS mutant allele specific imbalance show specific patterns of co-occurrence and mutual exclusion with alterations in key cancer genes like CDKN2A, TP53, STK11 and NKX2-1, often in a tumour type dependent manner. CONCLUSION: Advanced LUAD tumours exhibit higher copy-number alteration burden, with distinct alterations associated with tumour progression and metastasis. CDKN2A homozygous deletions predict poor prognosis in early disease, while KRAS mutant allele-specific imbalance is enriched in advanced tumours.

Humans↗
PubMed2026

Determinants of functional burden pleiotropy and gene dosage responses across human traits.

Pleiotropic and monotonic effects of gene dosage are central to understanding comorbidities in developmental pediatric and psychiatric disorders, yet the underlying biological processes are not well characterized. Here we develop a functional burden analysis to investigate the association of all protein-coding copy-number variants, genome-wide, with 43 complex traits in approximately 500,000 UK Biobank participants. We test variant associations disrupting 172 tissue or cell-type gene sets, finding associations for all traits, which we replicate in the All of Us cohort. Functional burden pleiotropy, defined as the number of traits significantly associated with a gene set, correlates with genetic constraint and is higher for brain than non-brain functions, even after normalizing for genetic constraint. Levels of pleiotropy, measured by burden correlation, are similar in deletions and loss-of-function single-nucleotide variants, and higher than in common variants and duplications. Most gene dosage responses are non-monotonic, with deletions and duplications showing same-direction effects, and monotonic responses decrease with genetic constraint. We observe associations between functional gene sets and traits for either deletions or duplications, but rarely both, with negatively correlated effect sizes. Together, these results link genetic constraint and brain-specific mechanisms to the whole-body multimorbidity of neurodevelopmental and psychiatric conditions.

Humans↗
PubMed2026

Aneuploidy selects for the acquisition of driver genes in breast cancer.

Chromosome instability is highly prevalent in cancer and drives large-scale chromosomal imbalances, known as aneuploidies1-4. How aneuploidy contributes to tumorigenesis remains difficult to study due to the vast numbers of genes affected. Here we established a CRISPR knockout- and activation-linked assay (CRISPR-KOALA), enabling high-throughput bidirectional genetic screens in immunocompetent mouse models of cancer. We developed a compendium of the ten most frequent human chromosome-arm-level alterations in basal-like breast cancer (BLBC), a disease type that is driven by large copy-number alterations (CNAs)5-8. Using CRISPR-KOALA, we screened the mouse orthologues of 3,752 genes on these arms and identified 90 cancer driver genes, the function of the vast majority of which is unknown. These genes drive distinct signalling pathways including MAPK, HIPPO and WNT, reflecting the high degree of BLBC heterogeneity. Manipulating the identified cancer driver genes overcomes the need for CNAs in Trp53-mutant BLBC mouse models. Mechanistically, we identify that PLGRKT is a potent oncogene that lies on chromosome 9p and show that its tumour-promoting activity is associated with highly stress-resistant mitochondria and an increased ability to detoxify reactive oxygen species. Together, our findings reveal that arm-level CNAs can function to select specific driver genes to promote heterogeneous biological processes.

Animals↗
PubMed2006

DNA copy-number analysis in bipolar disorder and schizophrenia reveals aberrations in genes involved in glutamate signaling.

Using bacterial artificial chromosome (BAC) array comparative genome hybridization (aCGH) at approximately 1.4 Mbp resolution, we screened post-mortem brain DNA from bipolar disorder cases, schizophrenia cases and control individuals (n=35 each) for DNA copy-number aberrations. DNA copy number is a largely unexplored source of human genetic variation that may contribute risk for complex disease. We report aberrations at four loci which were seen in affected but not control individuals, and which were verified by quantitative real-time PCR. These aberrant loci contained the genes encoding EFNA5, GLUR7, CACNG2 and AKAP5; all brain-expressed proteins with known or postulated roles in neuronal function, and three of which (GLUR7, CACNG2 and AKAP5) are involved in glutamate signaling. A second cohort of psychiatric samples was also tested by quantitative PCR using the primer/probe sets for EFNA5, GLUR7, CACNG2 and AKAP5, and samples with aberrant copy number were found at three of the four loci (GLUR7, CACNG2 and AKAP5). Further scrutiny of these regions may reveal insights into the etiology and genetic risk factors for these complex psychiatric disorders.

A Kinase Anchor Proteins↗
PubMed1992

Use of a cis-acting mutation to study the role of FLP-mediated recombination in the maintenance of native yeast 2 micrometer plasmids.

The 2 micrometer plasmid encodes a mechanism that ensures the partitioning of the plasmid at cell division. Little is known about the detailed mechanism of this partitioning system; for example, is there equal or unequal distribution of the plasmid molecules at mitosis? The plasmid also encodes a site-specific recombination system that is thought to be involved in plasmid copy-number amplification, although to date there has been no direct evidence that the recombination process itself is important for maintenance. We have identified a natural 2 micrometer variant that has a cis-acting mutation in the FLP-mediated recombination system. We show that this plasmid is unable to amplify in vivo. Our results demonstrate that the average copy number per cell is not affected for the mutant but there is a large clonal variation. This is a direct demonstration that plasmid partitioning results in an unequal distribution of plasmids and that FLP-mediated amplification compensates for this and therefore has an important role in maintenance.

DNA Nucleotidyltransferases↗
PubMed2026

Clinical and Genetic Spectrum of Large AIP Deletions.

Familial isolated pituitary adenoma (FIPA) accounts for approximately 2%-5% of all pituitary adenomas, with inactivating variants of the aryl hydrocarbon receptor-interacting protein (AIP) gene representing the most frequent known genetic cause. Clinically, patients with AIP variants often have young-onset macroadenomas with growth hormone hypersecretion, although disease severity and penetrance are variable. Most reported AIP variants are point mutations, whereas large deletions are rare and potentially underdiagnosed. Accurate detection of AIP copy-number variants requires methods such as multiplex ligation-dependent probe amplification or validated copy-number analysis of next-generation sequencing data, as Sanger sequencing alone may fail to identify these alterations. Due to the rarity of the disease, it is unknown whether large deletions in the ubiquitously expressed AIP gene are associated with potentially more severe phenotype. Available data suggest that large deletions may occur in 8%-10% of AIP mutation-positive pedigrees, highlighting the importance of incorporating copy-number variant detection into AIP testing workflows. We analysed data from all published patients with large AIP deletions (n = 25) and report here two novel large AIP deletions (Exons 3-4 and Exons 2-6 deletions) and three additional three families, including an Albanian kindred associated with metastatic H&#xfc;rthle cell thyroid carcinoma. No major differences compared with other AIP variants were found in age at diagnosis, tumour size, hormonal profile, sex distribution or presence of other tumours. A role for AIP variants in thyroid carcinogenesis is unlikely.

Humans↗
PubMed2025

Genomic and Immune Landscape of Pancreatic Ductal Adenocarcinoma Associated with Germline Pathogenic Variants in ATM.

PURPOSE: Germline pathogenic variants (PV) in ATM increase the risk of pancreatic ductal adenocarcinoma (PDAC), but the underlying tumor biology of PDAC associated with germline PV in ATM has not been adequately explored. EXPERIMENTAL DESIGN: Whole-genome, whole-exome, and RNA sequencing were performed on PDAC tumors from 25 germline ATM PV carriers diagnosed at Mayo Clinic between 2007 and 2017. Somatic and copy-number alterations, mutational signatures, transcriptomic subtypes, and the immune landscape were evaluated. RESULTS: High-quality whole-exome and whole-genome sequencing were obtained from 21 and 15 tumors, respectively. Biallelic inactivation of ATM was observed in 87%, KRAS PV in 90%, CDKN2A homozygous loss in 60%, and TP53 alterations in <10% of these tumors. A predominant clock-like mutational signature was present in all samples. Whole-transcriptome analysis identified that the aberrantly differentiated endocrine exocrine subtype accounted for 18% of PDAC and was consistently associated with >5-year overall survival. In addition, a 28-gene expression-based signature associated with overall survival was identified and further validated in The Cancer Genome Atlas cohort. Immune landscape analysis through CODEX identified enriched CD4 T-helper cell/tumor interactions and reduced B7H3-high cell/tumor interactions in ATM PV carriers compared with noncarriers. CONCLUSIONS: The observed absence of TP53 PV and enrichment for CDKN2A alterations in ATM tumors, along with differences in the mutational signatures, transcriptomic subtypes and immune landscape, improve our understanding of the mechanistic pathways involved in PDAC development in germline ATM PV carriers and help identify potential targeted therapeutic strategies.

Humans↗
PubMed2026

The Genomic Landscape of MYC-, MYCL-, and MYCN-Amplified Solid Tumors.

PURPOSE: MYC, MYCN, and MYCL amplifications are recurrent oncogenic events across solid tumors. Currently, no standardized selection biomarker is available to identify patients with MYC-dependent tumors. EXPERIMENTAL DESIGN: We analyzed copy-number alterations of MYC family genes and their features in more than 68,000 tumor-normal paired samples from pediatric and adult patients sequenced with MSK-IMPACT (Memorial Sloan Kettering-Integrated Mutation Profiling of Actionable Cancer Targets) and annotated with FACETS (Fraction and Allele-Specific Copy Number Estimates from Tumor Sequencing). The relationship between amplification features and MYC mRNA expression levels were evaluated in more than 10,000 samples from The Cancer Genome Atlas (TCGA). RESULTS: Across MSK Cancer Center samples, MYC amplifications were most common, found in 2,949 samples compared with 310 in MYCL and 217 in MYCN. Although MYCN and MYCL amplifications were predominantly focal (<10 Mb, 79% and 93%, respectively), MYC amplifications were frequently broader (>10 Mb, 62%). Although most tumor types showed similar features between broad and focal amplifications of MYC, in select cancer types, we identified differing co-occurrence and mutual exclusivity patterns with other disease-specific drivers. Furthermore, although MYC-amplified TCGA samples showed higher mRNA expression than wild-type ones, the focality of MYC amplification was seen to have limited influence on expression levels. CONCLUSIONS: Our results suggest that MYC dependency likely depends on many factors, including, but not limited to, total copy number of the detected amplification, lineage-specific factors, concomitant presence or absence of additional oncogenic alterations, and in some cases amplification focality.

Humans↗
PubMed2025

Extrachromosomal DNA-Driven Oncogene Dosage Heterogeneity Promotes Rapid Adaptation to Therapy in MYCN-Amplified Cancers.

UNLABELLED: Extrachromosomal DNA (ecDNA) amplification enhances intercellular oncogene dosage variability and accelerates tumor evolution by violating foundational principles of genetic inheritance through its asymmetric mitotic segregation. Spotlighting high-risk neuroblastoma, we demonstrate how ecDNA amplification undermines the clinical efficacy of current therapies in cancers with extrachromosomal MYCN amplification. Integrating theoretical models of oncogene copy number-dependent fitness with single-cell ecDNA quantification and phenotype analyses, we reveal that ecDNA copy-number heterogeneity drives phenotypic diversity and determines treatment sensitivity through mechanisms unattainable by chromosomal oncogene amplification. We demonstrate that ecDNA copy number directly influences cell fate decisions in cancer cell lines, patient-derived xenografts, and primary neuroblastomas, illustrating how extrachromosomal oncogene dosage-driven phenotypic diversity offers a strong evolutionary advantage under therapeutic pressure. Furthermore, we identify senescent cells with reduced ecDNA copy numbers as a source of treatment resistance in neuroblastomas and outline a strategy for their targeted elimination to improve the treatment of MYCN-amplified cancers. SIGNIFICANCE: ecDNA-driven tumor genome evolution provides a major challenge to curative cancer therapies. We demonstrate that ecDNA copy-number dynamics drives treatment resistance by promoting oncogene dosage-dependent phenotypic heterogeneity in MYCN-amplified cancers. Exploiting phenotype-specific vulnerabilities of ecDNA cells, therefore, presents a powerful strategy to overcome treatment resistance. See related commentary by Korsah, p. 1979.

Humans↗