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Background: Influenza A has been named as a priority pathogen by the WHO due to the potential to cause pandemics. Genomic sequencing of influenza strains is important to understand the evolution of the influenza strains and also to select the appropriate influenza vaccines to be used in the different influenza seasons in Sri Lanka. Therefore, we sought to understand the molecular epidemiology of the influenza viruses in the Western Province of Sri Lanka, including mutational analysis to investigate the evolutionary dynamics. Methodology: A total of 349 individuals presenting with fever and respiratory symptoms were enrolled in this study from November 2022 to May 2024. Nasopharyngeal and oropharyngeal specimens were collected and screened using quantitative PCR to detect Influenza A, Influenza B, and SARS-CoV-2. Subtyping and genomic sequencing was carried out on influenza A strains using Oxford Nanopore Technology. Results: Influenza A was detected in 49 (14 %) patients, influenza B in 20 (5.7%) and SARS-CoV-2 in 41 (11.7%). Co-infections were observed in five participants. The phylogenetic analysis assigned the H1N1 HA gene sequences within the 6B.1A.5a.2a clade. The HA gene of the H1N1 sequences in 2023 were assigned as belonging to the subclades C.1, C.1.2, and C.1.8, while the 2024 sequences were assigned to subclades C.1.8 and C.1.9. The H3N2 sequences from 2023 were assigned to the 3C.2a1b.2a.2a.1b clade and subclade G.1.1.2, while the 2024 sequences were assigned to the 3C.2a1b.2a.2a.3a.1 clade and subclade J.2. The K54Q, A186T, Q189E, E224A, R259K, K308R, I418V, and X215A amino acid substitutions were seen in the H1N1 in the 2023 and 2024 sequences. The 2024 H1N1 sequences additionally exhibited further substitutions, such as V47I, I96T, T120A, A139D, G339X, K156X, and T278S. Conclusion: In this first study using genomic sequencing to characterize the influenza A strains in Sri Lanka, which showed different influenza A viruses circulating in an 18-month period. As the Sri Lankan strains also had certain mutations of unknown significance, it would be important to continue detailed surveillance of the influenza strains in Sri Lanka to choose the most suitable vaccines for the population and the timing of vaccine administration.

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BACKGROUND: Malignant phyllodes tumors (MPT) are rare fibroepithelial breast cancers with no known effective systemic therapy; metastatic progression portends a dismal prognosis. We sought to describe the genomic landscape of MPTs through genomic profiling and immunotherapeutic biomarker analysis. MATERIALS AND METHODS: Cases of sequenced MPT were identified from a Clinical Laboratory Improvement Amendments-certified, College of American Pathologists-accredited laboratory (Foundation Medicine). All cases underwent genomic profiling using adaptor ligation-based, next-generation sequencing assay of 324 genes. Tumor agnostic immunotherapy biomarkers, microsatellite instability, tumor mutational burden (TMB), and programmed death-ligand 1 (PD-L1) expression were evaluated. Fisher's Exact Tests and analysis of variance were used to test for differences between groups and for continuous variables as appropriate. RESULTS: Of 135 MPT cases identified; 94 (69.6%) were localized/locally recurrent and 41 (30.4%) were metastatic. Median age was 54 years (range 14-86). The median TMB was 2.5 mut/Mb and 3 were TMB-high (≥10 mut/Mb). 21.4% were PD-L1+ via Dako 22C3 assay (CPS ≥1). Most commonly altered genes included TERT-promoter (69.7%), CDKN2A (45.9%), TP53 (37.8%), NF1 (35.6%), CDKN2B (33.3%), MED12 (28.9%), MTAP (27.7%), KMT2D (22.2%), PIK3CA (20.0%), PTEN (18.5%), and RB1 (18.5%). Several tumors harboring genomic alterations with US Food and Drug Administration-approved indications in other tumor types were found including NF1, PIK3CA, EGFR Exon 19/20 insertions, and BRAF V600E mutations. CONCLUSIONS: In the largest genomic evaluation of MPT to date, multiple clinically actionable mutations were found. Routine sequencing of metastatic MPT may provide additional information to guide treatment decisions and clinical trial enrollment.

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Background: Streptococcus dysgalactiae (SD) is an important pathogen in humans as well as in a broad range of animal species. Escalating rates of antibiotic resistance in SD has been reported in both human and veterinary clinical practice, but the dissemination of resistance determinants has so far never been examined in a One Health Perspective. We wanted to explore the occurrence of zoonotic transmission of SD and the potential for exchange of resistance traits between SD from different host populations. Methods: We compared whole genome sequences and phenotypical antimicrobial susceptibility of 407 SD isolates, comprising all isolates obtained from human bloodstream infections in 2018 (n = 274) and available isolates associated with animal infections from the years 2018 and 2019 (n = 133) in Norway. Results: Antimicrobial resistance genes were detected in 70 (26%), 9 (25%) and 2 (2%) of the isolates derived from humans, companion animals and livestock, respectively. Notably, distinct host associated genotypic resistomes were observed. The erm(A) gene was the dominant cause of erythromycin resistance in human associated isolates, whereas only erm(B) and lsa(C) were identified in SD isolates from animals. Moreover, the tetracycline resistance gene tet(O) was located on different mobile genetic elements in SD from humans and animals. Evidence of niche specialization was also evident in the phylogenetic analysis, as the isolates could be almost perfectly delineated in accordance with host species. Nevertheless, near identical mobile genetic elements were observed in four isolates from different host species including one human, implying potential transmission of antibiotic resistance between different environments. Conclusion: We found a phylogenetic delineation of SD strains in line with host adapted populations and niche specialization. Direct transmission of strains or genetic elements carrying resistance genes between SD from different ecological niches appears to be rare in our geographical region.

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INTRODUCTION: As population-based screening programs to identify genetic conditions in adults using genomic sequencing (GS) are increasingly available, validated patient-centered outcome measures are needed to understand participants' experience. We aimed to develop and validate an instrument to assess the perceived utility of GS in the context of adult screening. METHODS: Informed by a five-domain conceptual model, we used a five-step approach to instrument development and validation: (1) item writing, (2) cognitive testing, (3) pilot testing and item reduction, (4) psychometric testing, and (5) evaluation of construct validity. Adults undergoing risk-based or population-based GS who had received GS results as part of ongoing research studies participated in structured cognitive interviews and two rounds of surveys. After item pool refinement, we conducted an exploratory factor analysis and calculated Pearson correlations with related instruments. RESULTS: We derived the 18-item Adult Diagnostic version of the GENEtic Utility (GENE-U) scale (total sum score α = .87). Mirroring the Pediatric Diagnostic version, the instrument has a two-factor structure, including an Informational Utility subscale (14 items, α =.89) and an Emotional Utility subscale (4 items, α =.75). The Informational Utility subscale was strongly associated with empowerment and personal utility of GS. Correlations of the Emotional Utility subscale with psychosocial impact and anxiety and depression were weak to moderate. CONCLUSION: Initial psychometric testing of the Adult Screening GENE-U scale demonstrates its promise, and additional validation in translational genomics research is warranted.

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This study presents the comprehensive analysis of the genomic sequence of Klebsiella pneumoniae strain FAHZZU7042hy, having a 5,690,191 bp chromosome size. This strain was obtained from a blood sample of a patient suffering from severe neurological problems in Zhengzhou, China, 2023.

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Bacterial strains coded 21LM367, 21LM07, and 21LM1136 were isolated from the urine of patients with urinary tract infections (UTIs) at the Centre Hospitalier Régional de Daloa in Côte d'Ivoire. Based on average nucleotide identity (ANI) analysis, DNA-DNA digital hybridisation (dDDH), and other comparative genomic methods, strains 21LM07, 21LM367, and 21LM1136 were determined to be Priestia flexa. The size of the assembled complete genomes ranged from 8,624,538 to 4,007,501 bp. The average GC content was 37.76%, 46.33%, and 43.03% for strains 21LM07, 21LM367, and 21LM1136, respectively. The total number of coding regions (CDS) in each genome was 4172, 8497, and 6795, respectively, for strains 21LM07, 21LM367, and 21LM1136. Genomic prediction analysis revealed that a total of 4241, 8583, and 6881 genes were annotated in the 21LM07, 21LM367, and 21LM1136 genomes, respectively. No virulence or resistance genes were predicted in the genomes of strains 21LM07 and 21LM1136. On the other hand, two genes conferring resistance to beta-lactam and tetracyclines as well as nine virulence genes were predicted in the genome of 21LM367. In addition, 438, 350, and 153 mobile genetic elements (MGEs) were predicted in the genomes of strains 21LM367, 21LM1136, and 21LM07, respectively. Strain 21LM07 was characterised by the absence of plasmids in its genome. Two plasmids were predicted in the genomes of isolates 21LM367 and 21LM1136; however, rep7a and IncI2 were predicted to contain the tet(K) resistance gene. No typical multilocus sequences could be characterised in the genomes of the different strains.

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Canine distemper virus (CDV) triggers a severe, often fatal disease in dogs and wildlife known as canine distemper (CD). Prior research has noted significant genetic diversity and recombination among CDV isolates from different geographical regions, potentially contributing to vaccine failures. Despite this, no genetic characterization of Mongolian CDVs has been conducted. This study, isolated CDVs from three unvaccinated dogs: two 10-month-old mixed-breeds and an 18-month-old Samoyed. All exhibited CD symptoms and subsequently died. Virus isolation was conducted using Vero/dog SLAM cells, with genome sequencing performed via nanopore technology. The mixed-breed dogs were infected with non-recombinant CDV isolates, forming a sister clade to the Asia-1 lineage prevalent in Asia. The Samoyed was infected with a non-recombinant CDV isolate, classifying as Asia-4 lineage sporadically reported in some Asian countries. This sequencing data offers foundational information on genetic diversity, aiding CD control measure development and benefiting future Eurasia and Asian studies.

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Respiratory syncytial virus (RSV) is a significant cause of morbidity, particularly in infants. This study describes RSV genomic diversity and disease outcomes during the 2023-2024 season in the Johns Hopkins Hospital System (JHHS). Between August and December 2023, 406 patient samples were sequenced, showing that RSV-B GB5.0.5a was the dominant genotype detected. RSV-A genotype GA2.3.5 was detected less frequently. Metadata analysis of patient data revealed that, although RSV-B was more commonly detected, patients with RSV-A infections were more frequently hospitalized. Analysis of both the G- and F-genes revealed multiple amino acid substitutions in both RSV-A and RSV-B, with some positions within the F-protein that could be associated with evasion of antibody responses. Phylogenetic analysis revealed the genetic diversity of circulating GB5.0.5a and GA2.3.5 genotypes. This study serves as an important baseline for genomic surveillance of RSV within the JHHS and will assist in characterizing the impact of the newly approved RSV vaccines on RSV genomic evolution and the emergence of escape mutations.

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Plasmids are extrachromosomal DNA found in microorganisms. They often carry beneficial genes that help bacteria adapt to harsh conditions. Plasmids are also important tools in genetic engineering, gene therapy, and drug production. However, it can be difficult to identify plasmid sequences from chromosomal sequences in genomic and metagenomic data. Here, we have developed a new tool called PlasmidHunter, which uses machine learning to predict plasmid sequences based on gene content profile. PlasmidHunter can achieve high accuracies (up to 97.6%) and high speeds in benchmark tests including both simulated contigs and real metagenomic plasmidome data, outperforming other existing tools.

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The Hardy-Weinberg Equilibrium (HWE) is a fundamental principle employed in the analysis of genetic data, encompassing studies of meta-analysis and genomic sequencing. It has been demonstrated that HWE possesses the property of transitivity, wherein a multi-allelic polymorphism in equilibrium will persist in its equilibrium state even when alleles are deleted or combined. Nonetheless, the practice of filtering loci that do not adhere to HWE has been observed to impact the inference of population genetics within RADseq datasets. In response to this concern, the Robust Unified Test for HWE (RUTH) has been devised to consider population structure and genotype uncertainty, thereby offering a more precise evaluation of the quality of genotype data. Furthermore, deviations from HWE, such as extreme heterozygote excess, can be effectively utilized to identify genotyping errors or to pinpoint the presence of rare recessive disease-causing variants. In summary, it is evident that HWE holds immense significance in the field of genetic analysis, and its application in meta-analysis studies and genomic sequencing can yield invaluable insights into the intricacies of population structure and the genetics of diseases.

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Soil microbial flora constitutes a highly diverse and complex microbiome on Earth, often challenging to cultivation, with unclear metabolic mechanisms in situ. Here, we present a pioneering concept for the in situ construction of functional microbial consortia (FMCs) and introduce an innovative method for creating FMCs by utilizing phenanthrene as a model compound to elucidate their in situ biodegradation mechanisms. Our methodology involves single-cell identification, sorting, and culture of functional microorganisms, resulting in the formation of a precise in situ FMC. Through Raman-activated cell sorting-stable-isotope probing, we identified and isolated phenanthrene-degrading bacterial cells from Achromobacter sp. and Pseudomonas sp., achieving precise and controllable in situ consortia based on genome-guided cultivation. Our in situ FMC outperformed conventionally designed functional flora when tested in real soil, indicating its superior phenanthrene degradation capacity. We revealed that microorganisms with high degradation efficiency isolated through conventional methods may exhibit pollutant tolerance but lack actual degradation ability in natural environments. This finding highlights the potential to construct FMCs based on thorough elucidation of in situ functional degraders, thereby achieving sustained and efficient pollutant degradation. Single-cell sequencing linked degraders with their genes and metabolic pathways, providing insights regarding the construction of in situ FMCs. The consortium in situ comprising microorganisms with diverse phenanthrene metabolic pathways might offer distinct advantages for enhancing phenanthrene degradation efficiency, such as the division of labour and cooperation or communication among microbial species. Our approach underscores the importance of in situ, single-cell precision identification, isolation, and cultivation for comprehensive bacterial functional analysis and resource exploration, which can extend to investigate MFCs in archaea and fungi, clarifying FMC construction methods for element recycling and pollutant transformation in complex real-world ecosystems.

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BACKGROUND: The treatment landscape for HR(+)HER2(-) metastatic breast cancer (MBC) is evolving for patients with ESR1 mutations (mut) and PI3K/AKT pathway genomic alterations (GA). We sought to inform clinical utility for comprehensive genomic profiling (CGP) using tissue (TBx) and liquid biopsies (LBx) in HR(+)HER2(-) MBC. METHODS: Records from a de-identified breast cancer clinicogenomic database for patients who underwent TBx/LBx testing at Foundation Medicine during routine clinical care at ~ 280 US cancer clinics between 01/2011 and 09/2023 were assessed. GA prevalence [ESR1mut, PIK3CAmut, AKT1mut, PTENmut, and PTEN homozygous copy loss (PTENloss)] were calculated in TBx and LBx [stratified by ctDNA tumor fraction (TF)] during the first three lines of therapy. Real-world progression-free survival (rwPFS) and overall survival (rwOS) were compared between groups by Cox models adjusted for prognostic factors. RESULTS: ~ 60% of cases harbored 1 + GA in 1st-line TBx (1266/2154) or LBx TF ≥ 1% (80/126) and 26.5% (43/162) in LBx TF < 1%. ESR1mut was found in 8.1% TBx, 17.5% LBx TF ≥ 1%, and 4.9% LBx TF < 1% in 1st line, increasing to 59% in 3rd line (LBx TF ≥ 1%). PTENloss was detected at higher rates in TBx (4.3%) than LBx (1% in TF ≥ 1%). Patients receiving 1st-line aromatase inhibitor + CDK4/6 inhibitor (n = 573) with ESR1mut had less favorable rwPFS and rwOS versus ESR1 wild-type; no differences were observed for fulvestrant + CDK4/6 inhibitor (n = 348). CONCLUSION: Our study suggests obtaining TBx for CGP at time of de novo/recurrent diagnosis, followed by LBx for detecting acquired GA in 2nd + lines. Reflex TBx should be considered when ctDNA TF < 1%.

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PURPOSE: Critically ill infants from marginalized populations disproportionately receive care in neonatal intensive care units (NICUs) that lack access to state-of-the-art genomic care, leading to inequitable outcomes. We sought provider perspectives to inform our implementation study (VIGOR) providing rapid genomic sequencing within these settings. METHODS: We conducted semistructured focus groups with neonatal and genetics providers at 6 NICUs at safety-net hospitals, informed by the Promoting Action on Research Implementation in Health Services framework, which incorporates evidence, context, and facilitation domains. We iteratively developed codes and themes until thematic saturation was reached. RESULTS: Regarding evidence, providers felt that genetic testing benefits infants and families. Regarding context, the major barriers identified to genomic care were genetic testing cost, lack of genetics expertise for disclosure and follow-up, and navigating the complexity of selecting and ordering genetic tests. Providers had negative feelings about the current status quo and inequity in genomic care across NICUs. Regarding facilitation, providers felt that a virtual support model such as VIGOR would address major barriers and foster family-centered care and collaboration. CONCLUSION: NICU providers at safety-net hospitals believe that access to state-of-the-art genomic care is critical for optimizing infant outcomes; yet, substantial barriers exist that the VIGOR study may address.

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INTRODUCTION: Serratia marcescens is an opportunistic pathogen found ubiquitously in the environment and associated with a wide range of nosocomial infections. This multidrug-resistant bacterium has been a cause of concern for hospitals and healthcare facilities due to its ability to spread rapidly and cause outbreaks. Next generation sequencing genotyping of bacterial isolates has proven to be a valuable tool for tracking the spread and transmission of nosocomial infections. This has allowed for the identification of outbreaks and transmission chains, as well as determining whether cases are due to endogenous or exogenous sources. Evidence of nosocomial transmission has been gathered through genotyping methods. The aim of this study was to investigate the genetic diversity of carbapenemase-producing S. marcescens in an outbreak at a public hospital in Cuiaba, MT, Brazil. METHODOLOGY: Ten isolates of S. marcenses were sequenced and antibiotic resistance profiles analyzed over 12 days. RESULTS: The isolates were clonal and multidrug resistant. Gentamycin and tigecycline had sensitivity in 90% and 80% isolates, respectively. Genomic analysis identified several genes that encode ß-lactamases, aminoglycoside-modifying enzymes, efflux pumps, and other virulence factors. CONCLUSIONS: Systematic surveillance is crucial in monitoring the evolution of S. marcescens genotypes, as it can lead to early detection and prevention of outbreaks.

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We aimed to characterize SARS-CoV-2 infection in companion animals living in households with COVID-19-positive people and understand the dynamics surrounding how these animals become infected. Public health investigators contacted households with at least one confirmed, symptomatic person with COVID-19 for study recruitment. Blood, nasal, and rectal swab specimens were collected from pet dogs and cats and a questionnaire was completed. Specimens were tested for SARS-CoV-2 by RT-PCR, and for neutralizing antibodies; genomic sequencing was performed on viral-positive samples. A total of 36.4% of 110 pets enrolled had evidence of infection with SARS-CoV-2. Pets were more likely to test positive if the pet was immunocompromised, and if more than one person in the home was positive for COVID-19. Among 12 multi-pet households where at least one pet was positive, 10 had at least one other pet test positive. Whole-genome sequencing revealed the genomes of viral lineages circulating in the community during the time of sample collection. Our findings suggest a high likelihood of viral transmission in households with multiple pets and when pets had very close interactions with symptomatic humans. Further surveillance studies are needed to characterize how new variants impact animals and to understand opportunities for infection and spillover in susceptible species.

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Introduction: In October 2020, rapid prenatal exome sequencing (pES) was introduced into routine National Health Service (NHS) care in England, requiring the coordination of care from specialist genetics, fetal medicine (FM) and laboratory services. This mixed methods study explored the experiences of professionals involved in delivering the pES service during the first 2 years of its delivery in the NHS. Methods: A survey (n = 159) and semi-structured interviews (n = 63) with healthcare professionals, including clinical geneticists, FM specialists, and clinical scientists (interviews only) were used to address: 1) Views on the pES service; 2) Capacity and resources involved in offering pES; 3) Awareness, knowledge, and educational needs; and 4) Ambitions and goals for the future. Results: Overall, professionals were positive about the pES service with 77% rating it as Good or Excellent. A number of benefits were reported, including the increased opportunity for receiving actionable results for parental decision-making, improving equity of access to genomic tests and fostering close relationships between FM and genetics departments. Nonetheless, there was evidence that the shift to offering pES in a clinical setting had brought some challenges, such as additional clinic time, administrative processes, perceived lack of autonomy in decision-making regarding pES eligibility and difficulty engaging with peripheral maternity units. Concerns were also raised about the lack of confidence and gaps in genomics knowledge amongst non-genetics professionals - especially midwives. However, the findings also highlighted value in both FM, obstetric and genetics professionals benefiting from further training with a focus on recognising and managing prenatally diagnosed genetic conditions. Conclusion: Healthcare professionals are enthusiastic about the benefits of pES, and through multi-collaborative working, have developed relationships that have contributed to effective communication across specialisms. Although limitations on resources and variation in knowledge about pES have impacted service delivery, professionals were hopeful that improvements to infrastructure and the upskilling of all professionals involved in the pathway would optimise the benefits of pES for both parents and professionals.

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PURPOSE: Professional guidelines recommend engaging adolescents and young adults (AYAs) in medical decision making (DM), including whether to undergo genomic sequencing (GS). We explored DM around GS and attitudes after return of GS results among a diverse group of AYAs with cancer and their parents. METHODS: We surveyed AYAs with cancer (n = 75) and their parents (n = 52) 6 months after receiving GS results through the Texas KidsCanSeq study. We analyzed AYAs' DM role in GS research enrollment and their satisfaction with that role. We compared AYAs' and parents' self-reported understanding of, attitudes toward, and perceived utility of the AYA's GS results. RESULTS: Most AYAs reported equally sharing DM with their parents (55%) or leading DM (36%) about GS research. Compared with their cancer care DM role, 56% of AYAs reported the same level of involvement in GS research DM, whereas 32% were more involved, and 13% were less involved (P = .011). AYAs were satisfied (99%) with their DM role regarding GS study participation. AYAs and parents had similar self-reported understanding of, attitudes toward, and perceived utility of the GS results. CONCLUSION: Our results support engaging AYAs in DM about GS research and provide insights into AYAs' DM preferences and positive attitudes toward GS.

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Despite the emerging evidence in recent years, successful implementation of clinical genomic sequencing (CGS) remains limited and is challenged by a range of barriers. These include a lack of standardized practices, limited economic assessments for specific indications, limited meaningful patient engagement in health policy decision-making, and the associated costs and resource demand for implementation. Although CGS is gradually becoming more available and accessible worldwide, large variations and disparities remain, and reflections on the lessons learned for successful implementation are sparse. In this commentary, members of the Global Economics and Evaluation of Clinical Genomics Sequencing Working Group (GEECS) describe the global landscape of CGS in the context of health economics and policy and propose evidence-based solutions to address existing and future barriers to CGS implementation. The topics discussed are reflected as two overarching themes: (1) system readiness for CGS and (2) evidence, assessments, and approval processes. These themes highlight the need for health economics, public health, and infrastructure and operational considerations; a robust patient- and family-centered evidence base on CGS outcomes; and a comprehensive, collaborative, interdisciplinary approach.

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The world has seen unprecedented gains in the global genomic surveillance capacities for pathogens with pandemic and epidemic potential within the last 4 years. To strengthen and sustain the gains made, WHO is working with countries and partners to implement the Global Genomic Surveillance Strategy for Pathogens with Pandemic and Epidemic Potential 2022-2032. A key technical product developed through these multi-agency collaborative efforts is a genomics costing tool (GCT), as sought by many countries. This tool was developed by five institutions - Association of Public Health Laboratories, FIND, The Global Fund to Fight AIDS, Tuberculosis and Malaria, UK Health Security Agency, and the World Health Organization. These institutions developed the GCT to support financial planning and budgeting for SARS-CoV-2 next-generation sequencing activities, including bioinformatic analysis. The tool costs infrastructure, consumables and reagents, human resources, facility and quality management. It is being used by countries to (1) obtain costs of routine sequencing and bioinformatics activities, (2) optimize available resources, and (3) build an investment case for the scale-up or establishment of sequencing and bioinformatics activities. The tool has been validated and is available in English and Russian at https://www.who.int/publications/i/item/9789240090866. This paper aims to highlight the rationale for developing the tool, describe the process of the collaborative effort in developing the tool, and describe the utility of the tool to countries.

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BACKGROUND: Young patients with breast ductal carcinoma in situ (DCIS) often face a poorer prognosis. The genomic intricacies in young-onset DCIS, however, remain underexplored. METHODS: To address this gap, we undertook a comprehensive study encompassing exome, transcriptome, and vmethylome analyses. Our investigation included 20 DCIS samples (including 15 young-onset DCIS) and paired samples of normal breast tissue and blood. RESULTS: Through RNA sequencing, we identified two distinct DCIS subgroups: "immune hot" and "immune cold". The "immune hot" subgroup was characterized by increased infiltration of lymphocytes and macrophages, elevated expression of PDCD1 and CTLA4, and reduced GATA3 expression. This group also exhibited active immunerelated transcriptional regulators. Mutational analysis revealed alterations in TP53 (38%), GATA3 (25%), and TTN (19%), with two cases showing mutations in APC, ERBB2, and SMARCC1. Common genomic alterations, irrespective of immune status, included gains in copy numbers at 1q, 8q, 17q, and 20q, and losses at 11q, 17p, and 22q. Signature analysis highlighted the predominance of signatures 2 and 1, with "immune cold" samples showing a significant presence of signature 8. Our methylome study on 13 DCIS samples identified 328 hyperdifferentially methylated regions (DMRs) and 521 hypo-DMRs, with "immune cold" cases generally showing lower levels of methylation. CONCLUSION: In summary, the molecular characteristics of young-onset DCIS share similarities with invasive breast cancer (IBC), potentially indicating a poor prognosis. Understanding these characteristics, especially the immune microenvironment of DCIS, could be pivotal in identifying new therapeutic targets and preventive strategies for breast cancer.

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