Clonal haematopoiesis occurs when a haematopoietic stem cell acquires a somatic mutation that gives it a survival or proliferation advantage, allowing it to outcompete normal stem cells and produce an expanding fraction of the body’s blood cells. The phenomenon becomes increasingly common with age, and its presence in blood DNA can be detected through sequencing long before any disease develops. Researchers have previously tied clonal haematopoiesis to heightened risks of blood cancers, heart attacks and strokes, but its role in infectious disease has remained far less clear. The new study, led by Eleanor Fewings of the Illumina Artificial Intelligence Laboratory together with collaborators at the Broad Institute, Massachusetts General Hospital, Vanderbilt University Medical Center and Memorial Sloan Kettering Cancer Center, set out to answer that question at unprecedented scale.

The team assembled genetic and clinical data from three population cohorts totalling 590,537 individuals, applying a multi-parameter somatic variant calling and filtering pipeline designed to detect even low-frequency mutations in blood-derived DNA with high confidence. Across 43 genes implicated in clonal haematopoiesis, they identified 19,822 mutations in 40,560 people, corresponding to a prevalence of 6.87 percent. To guard against spurious findings, the researchers then validated their results in a combined analysis encompassing 889,215 individuals, one of the largest somatic genetics investigations ever conducted. The sheer scale of the resource allowed them to dissect risk not just for clonal haematopoiesis as a whole, but for individual mutated genes, specific recurrent mutations and expanding clones defined by variant allele fraction, a measure of the proportion of blood cells carrying the mutation.

The central result was unambiguous: people with clonal haematopoiesis were significantly more likely to develop serious bacterial infection, with a hazard ratio of 1.22 and a p-value of 4.66 × 10⁻²⁹, an association so statistically strong that chance can be essentially excluded. The effect was independent of haematological malignancy, meaning it was not simply a case of undiagnosed cancer causing infections, and it remained robust after adjustment for inflammatory comorbidities and genetic ancestry. Perhaps most strikingly, clonal haematopoiesis was also associated with a 1.84-fold increase in mortality within 28 days of infection, indicating that the mutations do not merely raise the likelihood of becoming infected but also compromise the body’s ability to survive the encounter.

The study’s most clinically consequential contribution, however, lies in its demonstration that risk is strongly dose-dependent and mutation-specific. Among individuals carrying recurrent mutations in five particular genes, SRSF2, DNMT3A, SF3B1, IDH2 and NRAS, a group numbering 2,143 people, the absolute risks were substantial. For those with expanded SRSF2 P95 clones, a specific recurrent mutation in a splicing factor gene, between 22 and 25 percent developed a serious bacterial infection within ten years. That figure rivals the predictive power of well-established clinical risk factors and suggests that a single detectable point mutation in a blood sample can flag a person as being at markedly elevated infectious risk years in advance.

The mechanistic logic behind these associations is rooted in what the mutated genes actually do. DNMT3A encodes a DNA methyltransferase essential for normal stem cell differentiation, while SRSF2 and SF3B1 are splicing factors that govern how RNA transcripts are processed, and IDH2 and NRAS participate in metabolic and signalling pathways respectively. When these genes are disrupted, the resulting blood cells can behave abnormally in ways that impair innate and adaptive immunity, including altered production of inflammatory cytokines and compromised function of neutrophils and macrophages, the cellular workhorses of bacterial defence. The new epidemiological findings align with this biology, showing that the immune consequences of clonal haematopoiesis are not confined to cancer predisposition but extend to everyday host defence against bacteria.

Importantly, the associations held across diverse populations and were largely independent of the specific bacterial strain involved, suggesting a broad, generalised weakening of antibacterial immunity rather than vulnerability to any single pathogen. This universality strengthens the case that clonal haematopoiesis acts as a systemic modifier of immune competence. It also helps explain a long-standing clinical observation: older adults vary enormously in their susceptibility to sepsis and pneumonia, and much of that variation has remained unexplained by conventional risk factors such as diabetes, chronic kidney disease or immunosuppressive medication. Somatic mutations in the blood may account for a meaningful share of that unexplained risk.

The study was made possible by an extraordinary confluence of large-scale biobank resources, including the UK Biobank, Genomics England’s National Genomic Research Library and the BioVU biobank at Vanderbilt University Medical Center, with sequencing of 250,000 whole genomes funded by the Alliance for Genomic Discovery, a consortium of NashBio, Illumina and several pharmaceutical partners. This infrastructure reflects a broader shift in biomedical research toward population-scale sequencing, in which millions of routinely collected blood samples become windows into the somatic evolution occurring inside the body. What was once visible only through the lens of leukaemia genomes can now be quantified across entire populations, revealing subtle but consequential effects on common diseases.

The implications for clinical practice are potentially far-reaching. If clonal haematopoiesis screening were incorporated into routine care, individuals with high-risk clones, particularly expanded SRSF2 mutations, could be flagged for closer monitoring, earlier vaccination strategies, aggressive management of modifiable infection risks or a lower threshold for empirical antibiotic treatment when symptoms appear. The findings also raise the prospect of therapies that target the mutated clones themselves or their inflammatory downstream effects, an area of intense pharmaceutical interest given the established links between clonal haematopoiesis and cardiovascular disease. Several companies are already developing agents aimed at damping the inflammation driven by these clones, and infection risk may now join cardiovascular events and malignancy as an outcome worth tracking in such trials.

Caveats remain. The study is observational, and while the authors adjusted extensively for malignancy, comorbidities and ancestry, residual confounding cannot be fully excluded, and the precise molecular mechanisms connecting each mutation to impaired bacterial clearance will require experimental work in cellular and animal models. The published version is also an accepted manuscript shared early for rapid access and is subject to further editorial refinement. Nevertheless, the consistency of the dose-dependent signal across hundreds of thousands of people, multiple cohorts and diverse ancestries makes a compelling case that clonal haematopoiesis deserves recognition as a genuine risk factor for serious bacterial infection. For the millions of people who carry these silent mutations, the study transforms a hidden aspect of biological ageing into an actionable piece of medical information, and it signals that the era of somatic mutation screening for non-cancer diseases may be arriving faster than anyone anticipated.

Subject of Research: Association of clonal haematopoiesis mutations with risk of serious bacterial infection

Article Title: Clonal haematopoiesis subtypes confer dose-dependent risk of serious bacterial infection

Article References: Fewings, E., Yu, Z., Gutierrez, J. C., Truong, B., Fiziev, P. P., McRae, J., Schwartzentruber, J., Bick, A. G., Natarajan, P., Lareau, C. A., Ulirsch, J. C., & Farh, K. K.-H. (2026). Clonal haematopoiesis subtypes confer dose-dependent risk of serious bacterial infection. Nature Communications. https://doi.org/10.1038/s41467-026-77934-x

Image Credits: AI Generated

DOI: 10.1038/s41467-026-77934-x

Keywords: clonal haematopoiesis, somatic mutations, serious bacterial infection, SRSF2, DNMT3A, SF3B1, IDH2, NRAS, haematopoietic stem cells, sepsis, population genomics, immune ageing

The study, led by Antonella Manca, Maria Cristina Sini, and Giuseppe Palmieri of the Institute of Genetic and Biomedical Research at Italy’s National Research Council in Sassari, together with colleagues in Florence, Perugia, and Genoa, examined 76 paired tumor samples — 38 primary melanomas and the first detected metastasis from each of the same 38 patients. All patients had advanced disease at the time of enrollment. The researchers profiled mutations across 517 genes spanning the key oncogenic pathways using next-generation sequencing, and in parallel performed reduced representation bisulfite sequencing (RRBS), a technique that maps methylation changes at CpG islands, the short stretches of DNA rich in cytosine-guanine dinucleotides where methylation most often regulates gene activity.

The genetic results were, in a sense, reassuringly boring. When the team compared primary tumors with their matched metastases, they found no statistically significant discrepancies in the mutational status of the main pathways that control cell proliferation and survival in melanoma: MAPK, PI3K/AKT, and INK4/ARF. Discordance between paired samples was relatively uncommon — 15.8 percent of patients for BRAF, 7.9 percent for NRAS, 21.1 percent for PI3K/AKT pathway genes, and 23.7 percent for INK4/ARF. In other words, the metastasis largely inherits the mutation profile of the primary tumor it came from, at least within the canonical drivers of melanomagenesis.

But one genetic metric told a different story. Tumor mutation burden, or TMB — the density of mutations per megabase of DNA, widely used as a proxy for how immunogenic a tumor should be — dropped significantly between primary tumors and metastases in a meaningful fraction of cases. Among the discordant pairs, seven patients had a high-TMB primary tumor but a low-TMB metastasis, while only one showed the reverse pattern, a statistically significant imbalance (p = 0.003). Overall, two-thirds of the patients (25 of 38) had primary melanomas with high TMB, defined as more than 10 mutations per megabase, yet in roughly a quarter of those cases (7 of 25), the paired metastasis had lost that high-mutation load. The authors propose that this loss of mutational burden during progression may reduce the immunogenicity of the tumor, helping metastases evade immune surveillance and contributing to the immunosuppressive microenvironment their group had previously described in the same cohort.

The methylation data, by contrast, revealed a striking and systematic shift. Principal component analysis of the RRBS profiles showed a clear separation between primary tumors and metastases, with methylation levels declining after progression to metastasis — a difference significant at p < 0.01. Notably, this epigenetic drift did not correlate with the anatomic site of the distant metastasis, nor with TMB, BRAF status, or alterations in the main melanomagenesis pathways. The implication is provocative: the epigenetic reprogramming that accompanies metastasis appears to unfold along its own trajectory, largely decoupled from the intracellular mutation landscape that is usually the focus of molecular tumor profiling.

Digging into the differentially methylated regions, the researchers found a coherent epigenetic program that reads like a blueprint for metastatic behavior. In samples from patients with advanced disease (AJCC stages IIIB to IV), two major patterns emerged. First, genes acting as tumor suppressors or inhibitors of cell growth showed hypermethylation — a modification typically associated with gene silencing — which would favor uncontrolled proliferation and the loss of differentiated characteristics, a process known as dedifferentiation. Second, genes involved in cytoskeletal remodeling, invasion, and neuronal signaling showed hypomethylation, consistent with the well-recognized neuron-like reprogramming of melanoma cells. Melanocytes, after all, share a developmental lineage with neural crest cells, and melanomas that reactivate this neural program tend to be more invasive and more capable of spreading.

When the team clustered primary tumors by their methylation profiles, three distinct subtypes emerged: a poorly methylated group, an intermediate group, and a group displaying the CpG island methylator phenotype, or CIMP, in which many CpG islands across the genome acquire methylation simultaneously. This classification, familiar from other cancers such as colorectal and glioblastoma, had not been clearly mapped against clinical outcomes in paired melanoma samples before. The researchers then asked the clinically crucial question: does the methylation class of the primary tumor predict how patients fare?

The answer, with the numbers available, was a cautious no — but with an intriguing hint. For overall survival, analyzed in 38 patients, the log-rank test found no significant differences among the three methylation groups (p = 0.36), and univariate Cox models confirmed the lack of significance, with a hazard ratio of 0.56 for the intermediate versus low group (p = 0.196) and 1.05 for CIMP versus low (p = 0.921). Progression-free survival, measured from primary diagnosis to first relapse in 36 patients, told the same story (p = 0.6). When the low and CIMP groups were merged into a single category, the trend toward a survival difference strengthened but still fell short of statistical significance (p = 0.15). Yet the raw numbers were suggestive: 84 percent of patients in the low and CIMP categories died during follow-up (21 of 25), compared with 54 percent in the intermediate group (7 of 13), yielding a hazard ratio of 1.81. The authors are candid about the limitation — the sample size of 38 patients is simply too small to detect moderate survival differences with confidence — but they argue that the consistent trend toward longer survival for patients whose primary tumors show intermediate methylation deserves confirmation in larger cohorts.

The broader significance of the study lies in how it reframes the relationship between genetics and epigenetics in cancer progression. Targeted therapies and immunotherapies in melanoma are largely built on the genetic framework: BRAF inhibitors for BRAF-mutant disease, and immune checkpoint inhibitors whose efficacy correlates with mutation burden. If, as this study suggests, metastases can shed their high-TMB character while acquiring a coordinated hypomethylation program that promotes invasion and neural-like plasticity, then the molecular portrait a clinician sees at metastasis may differ in clinically meaningful ways from the one painted at diagnosis — even when the driver mutations are identical. The finding that methylation changes proceed independently of mutation status also raises the possibility that epigenetic therapies, such as DNA methyltransferase inhibitors, could target vulnerabilities that genetic profiling alone would miss.

For now, the study’s authors, writing on behalf of the EPICA consortium and funded by the Fondazione AIRC, frame their work as a step toward integrating methylation profiling into the molecular workup of melanoma. The paired-sample design — comparing primary tumors and metastases within the same patient, rather than across unrelated cohorts — is a methodological strength that controls for the enormous inter-patient variability that has complicated earlier epigenetic studies. The consistent directional changes they observed, from global hypomethylation in metastases to the hypermethylation of tumor suppressor genes and the hypomethylation of invasion-related genes, paint a picture of metastasis as an epigenetic achievement as much as a genetic one. Whether the intermediate methylation class ultimately proves to be a prognostic marker will require larger studies, but the message of this work is already clear: to understand how melanoma kills, researchers may need to read not just the sequence of the genome, but the chemical script written upon it.

Subject of Research: DNA methylation and mutation changes during melanoma progression from primary tumors to matched metastases

Article Title: Impact of methylation and mutation modifications on melanoma progression through evaluation of paired primary and secondary lesions from same patients

Article References: Manca, A., Sini, M. C., Nuvoli, L., Simi, S., Costabile, S., Bellezza, G., De Giorgi, V., Guadagno, A., Ghiorzo, P., Mandalà, M., Massi, D., Palmieri, G., on behalf of the Epigenetic Immune-Oncology Consortium AIRC (EPICA), Maio, M., Anichini, A., Pfeffer, U., & Cossu, A. (2026). Impact of methylation and mutation modifications on melanoma progression through evaluation of paired primary and secondary lesions from same patients. Journal of Translational Medicine, 24(1), Article 1280. https://doi.org/10.1186/s12967-026-09082-1

Image Credits: AI Generated

DOI: 10.1186/s12967-026-09082-1

Keywords: melanoma, DNA methylation, epigenetics, tumor mutation burden, metastasis, CIMP, RRBS, BRAF, NRAS, tumor microenvironment, prognosis, paired tumor samples

Ferroptosis is not the tidy, programmed self-destruction of apoptosis. It is a messier, iron-driven form of cell death in which lipid peroxides accumulate in cell membranes until they rupture. Discovered formally just over a decade ago, ferroptosis has since been implicated in cancer, cardiovascular disease, neurodegeneration, and inflammatory disorders. What makes it especially relevant to endometriosis is the disease’s own biochemistry. Endometriotic lesions shed blood into the peritoneal cavity month after month, flooding the local environment with free iron. Studies have documented that this iron overload can trigger ferroptotic damage in granulosa cells of the ovary and even in early embryos, contributing to the infertility that so often accompanies the disease. Retrograde menstruation—the reflux of endometrial tissue through the fallopian tubes into the pelvic cavity—is widely accepted as the initiating event of endometriosis, and ferroptosis may facilitate the survival and implantation of ectopic endometrial cells as they migrate and colonize new territory.

The research team, led by Buhaiqiemu Kadeer and corresponding author Zhifang Chen, assembled their evidence from the Gene Expression Omnibus, a public repository of gene expression data maintained by the National Center for Biotechnology Information. They cross-referenced these endometriosis datasets with the FerrDb database, a manually curated catalog of genes that regulate or mark ferroptosis. From this intersection they extracted the raw material for a multilayered computational investigation that pooled an array of modern bioinformatic techniques: differential expression analysis with the Limma package, weighted gene co-expression network analysis to find groups of genes acting in concert, functional enrichment through Gene Ontology, KEGG pathway, and Metascape frameworks, and a protein-protein interaction network to map which gene products physically and functionally connect.

The initial screen was striking. The analysis revealed 18 differentially expressed genes tied to ferroptosis in endometriotic tissue, along with 36 genes from co-expression modules that clustered with the disease state. When the researchers overlapped and filtered these candidates, eleven core genes emerged. From there, the team deployed two complementary machine learning strategies to distill the list further: LASSO regression, a statistical technique that penalizes complexity and prunes away weak predictors, and the Random Forest algorithm, an ensemble method that builds hundreds of decision trees and votes on the most informative features. Both approaches converged on the same six genes—BRD7, OSBPL9, AGPS, NRAS, PEX12, and NCOA4—suggesting that this sextet carries genuine signal rather than statistical noise.

Each of the six genes tells a biologically coherent story about why iron metabolism and lipid chemistry might matter in endometriosis. NCOA4, or nuclear receptor coactivator 4, is the cargo receptor that delivers ferritin—the cell’s iron storage cage—to autophagy machinery for destruction, a process aptly named ferritinophagy. When NCOA4 ramps up, stored iron is released into the cytoplasm, raising the intracellular iron pool and pushing cells closer to the ferroptotic threshold. AGPS encodes an enzyme at the heart of ether lipid biosynthesis, and ether lipids are among the most vulnerable substrates for the peroxidation reactions that drive ferroptosis. PEX12, a peroxisomal biogenesis factor, connects to peroxisome function, an organelle intimately involved in very-long-chain fatty acid and lipid metabolism. OSBPL9 belongs to the oxysterol-binding protein family, tying the picture to cholesterol and sterol transport, while NRAS—a well-known signaling oncogene—and BRD7, a chromatin regulator with anti-inflammatory and tumor-suppressive roles, link ferroptosis to the proliferation and inflammatory signaling characteristic of endometriotic lesions.

To test whether these six genes could actually tell a sick sample from a healthy one, the researchers built a multi-gene logistic regression model and evaluated its diagnostic performance. The model showed high diagnostic value for distinguishing endometriosis from non-diseased tissue, positioning the six-gene panel as a candidate blood- or tissue-based biomarker signature. Because endometriosis currently lacks any validated non-invasive molecular test, a gene expression signature with strong discriminatory power would represent a meaningful advance, potentially allowing earlier intervention before lesions, adhesions, and fertility damage become entrenched.

But the study went beyond diagnosis to probe the immune landscape of the disease. Using CIBERSORT, a computational tool that estimates the proportions of different immune cell types within bulk tissue expression data, the team found that alterations in the endometriotic immune microenvironment appear closely related to the six hub genes. This is a significant observation because endometriosis is increasingly understood as an inflammatory and immune-dysregulated condition. Lesions are infiltrated by macrophages, and immune cells in the peritoneal cavity often fail to clear refluxed endometrial cells effectively. The correlation between ferroptosis-related gene expression and immune cell composition suggests that iron-driven cell death and immune dysfunction may feed into one another, each amplifying the other in a vicious cycle that sustains lesion growth and inflammation.

The final layer of the analysis reached upward in the regulatory hierarchy, from genes to the microRNAs that control them. By constructing a miRNA-target regulatory network, the researchers predicted three key microRNAs—hsa-mir-125a-5p, hsa-mir-218-5p, and hsa-mir-124-3p—as potential upstream modulators of the hub genes. These small RNA molecules fine-tune protein production by binding messenger RNAs, and each of the three has independent credentials in reproductive biology. MiR-124-3p has been shown to influence endometrial receptivity by altering epithelial cell polarity and adhesion, and it is upregulated in the endometrium and serum of women with chronic endometritis. MiR-125a-5p has been studied in ischemia-reperfusion injury and inflammatory contexts, while miR-218-5p participates in neuroinflammatory regulation. Together, the three microRNAs offer a second tier of candidate biomarkers and potential drug targets, since manipulating a single microRNA can influence multiple genes in a pathway simultaneously.

The authors are careful to frame their work as hypothesis-generating. All of the data derive from publicly available, previously published and fully de-identified datasets, so no new biological samples were collected, and the computational predictions will need validation in independent cohorts of patients, ideally using clinical specimens and prospective study designs. Nonetheless, the convergence of machine learning, network biology, and immunology around a single gene panel offers a template for how complex, poorly understood diseases can be interrogated computationally before expensive clinical trials begin. The study was funded by research projects examining NCOA4-mediated iron autophagy and ferroptosis in endometriosis, indicating that the team intends to pursue these mechanisms experimentally.

If the six-gene signature and its three regulatory microRNAs hold up under experimental and clinical scrutiny, the implications could extend well beyond diagnostics. Genes like NCOA4 and AGPS sit at control points of iron handling and lipid peroxidation that are already attracting pharmaceutical interest, with ferroptosis-inducing and ferroptosis-inhibiting compounds under investigation in oncology. Repurposing or refining such agents for endometriosis could open an entirely new therapeutic avenue for a disease whose current treatments—hormonal suppression and surgery—manage symptoms but rarely cure the condition. For millions of women waiting for an answer and an effective treatment, a molecular map of ferroptosis in their lesions may prove to be the first genuinely new lead in decades.

Subject of Research: Ferroptosis-related genes as diagnostic and predictive biomarkers in endometriosis identified through integrated bioinformatic analysis

Article Title: Diagnostic and Predictive Values of Ferroptosis-Related Genes in Endometriosis Based on Integrated Bioinformatic Analysis

Article References: Kadeer, B., Wufuer, S., Maimaitimin, A., Ablat, N., Li, X., & Chen, Z. (2026). Diagnostic and Predictive Values of Ferroptosis-Related Genes in Endometriosis Based on Integrated Bioinformatic Analysis. Reproductive Sciences. https://doi.org/10.1007/s43032-026-02142-3

Image Credits: AI Generated

DOI: 10.1007/s43032-026-02142-3

Keywords: endometriosis, ferroptosis, biomarkers, NCOA4, BRD7, AGPS, NRAS, PEX12, OSBPL9, microRNA, bioinformatics, immune infiltration