Persistent pathological structures, such as tumors, fibrotic nodules, granulomas, microbial biofilms, or protein aggregates, are traditionally viewed as age-related conditions that emerge after reproduction, when natural selection is less effective at eliminating traits expressed late in life. However, some pathologies with robust and organized architectures can arise surprisingly early, challenging this classical perspective. We recently proposed that intra-organismal selection for function, a selective process operating within organisms and acting on non-reproducing entities by favoring structural configurations that enhance stability, robustness, and novelty generation, may play a role in aging. Here, we suggest that this same process can also operate well before the so-called selection shadow (i.e., life stages where natural selection is too weak to purge deleterious mutations). We identify three non-mutually exclusive mechanisms that may promote this early-life action: (i) initial local adaptive benefits, such as improved tissue repair or containment of infection; (ii) limited or context-specific fitness costs, allowing structurally stable but abnormal configurations to persist undetected; and (iii) rapid environmental changes that reshape tissue-level selective landscapes, driven by pollutants, endocrine disruptors, or novel diets. Recognizing early-onset organized pathologies as by-products of eco-evolutionary tissue dynamics, rather than as mere developmental errors, reframes their biological significance and opens new therapeutic avenues. Instead of targeting cells exclusively, future strategies could focus on disrupting the functional architecture of pathological tissues and structures, offering novel means to prevent or control early-life diseases shaped by internal selection forces.

BACKGROUND:Microsatellite instability (MSI) and mismatch repair (MMR) deficiency are key predictive biomarkers for immune checkpoint inhibitors (ICIs) in metastatic colorectal cancer (mCRC). In real-world practice, however, diagnostic pathways often involve heterogeneous testing modalities, which may lead to discordant or inconclusive results. METHODS:We conducted a retrospective study of patients with mCRC who underwent at least one MSI/MMR assessment between 2015 and 2025. Diagnostic modalities included IHC, tissue-based and liquid-based MSI testing. A predefined decision algorithm classified results as conclusive or inconclusive; discordant cases underwent adjudication that integrated a pathology review, molecular features, and technical considerations. Patients were ultimately assigned to definitive MSS or definitive MSI groups. Clinical characteristics, treatment patterns, and outcomes-particularly in relation to immunotherapy-were evaluated. RESULTS:Among 727 evaluable patients, the MSI/MMR status was conclusive in 695 (95.6%) and inconclusive in 32 (4.4%). Inconclusive cases resulted from isolated MMR protein loss, heterogeneous or equivocal staining, inter-tumoral discordance, or discrepancies between tissue- and liquid-based assays. After adjudication, 54 patients (7.4%) were classified as definitive MSI and 673 (92.6%) as definitive MSS. Definitive MSI tumors were associated with female sex, right-sided primaries, high-grade histology, nodal involvement, and BRAF V600E mutations. Among the definitive MSI patients, 31 (57.4%) received immunotherapy, achieving a complete response rate of 48.4% and an overall response rate of 71.0%. Median PFS and OS were not reached in the definitive MSI group, whereas definitive MSS patients treated with ICIs experienced significantly poorer outcomes. Conclusive and adjudicated MSI groups demonstrated comparable responses to immunotherapy. CONCLUSIONS:In real-world practice, a meaningful proportion (4%) of mCRC patients experience inconclusive MSI/MMR assessment, with important clinical implications. Both technical and biological factors contribute to diagnostic uncertainty. Integrating orthogonal testing modalities and applying structured adjudication improves classification accuracy and ensures appropriate access to immunotherapy.

Pathological processes are often conceptualized as localized phenomena anchored in a primary tumor, a focal lesion, or a single organ. However, growing evidence indicates that many diseases persist and progress as complex distributed systems, maintained by interactions among multiple sites. Building on the emerging framework of selection for function, which can be applied to understand the evolutionary persistence of both replicating and non-replicating entities, we propose that metastases, amyloidoses, fibroses, autoimmune syndromes, granulomatous diseases, and multifocal reproductive disorders can all be understood as complex evolving pathological systems within individuals. In these contexts, local units such as metastatic nodules, amyloid plaques, or fibrotic foci act as semi-autonomous entities, yet achieve collective persistence through systemic flows, feedback loops, and network-level interactions, where local structuration gives rise to systemic effects. At certain points, lesions that produce mediators can trigger systemic alterations that, in turn, favor the emergence and persistence of additional lesions. This creates a vicious cycle in which local and systemic dynamics reinforce one another, helping these specific pathological networks to overcome host defense mechanisms and persist (i.e., be 'selected' via differential persistence). This perspective unifies seemingly disparate conditions under the principle of system persistence, reframing pathology as an emergent organizational property of a pathological system rather than as isolated local breakdowns of organismal components. It also carries important implications for evolutionary medicine, suggesting a taxonomy of diseases that distinguishes localized from distributed functional pathologies. Clinically, it underscores the need to go beyond focal interventions, advocating instead for therapies that disrupt pathological connectivity, destabilize network coherence, and monitor systemic biomarkers of disease persistence. Recognizing the role of selection for function in the emergence and persistence of complex pathological systems opens new avenues for both theoretical integration and therapeutic innovation in evolutionary medicine.

Many cancer therapies achieve durable control without complete tumor eradication, suggesting that disrupting tumor organization may be more critical than killing cells. We propose that effective treatments converge by destabilizing the tumor's Group Phenotypic Composition (GPC), the functional and spatial organization of interacting cell populations. When this organization collapses, tumors lose coherence. This perspective provides a unifying framework for designing therapies targeting tumor-level dynamics rather than cell number alone.

Background/Objectives: The prognostic significance of blood tumor mutational burden (bTMB) in metastatic colorectal cancer (mCRC) remains poorly defined. While tissue-based TMB has been associated with favorable outcomes in selected colorectal cancer subgroups, the clinical meaning of bTMB in real-world practice is unclear. This study evaluated the prognostic impact of bTMB measured through liquid biopsy in an unselected cohort of patients with mCRC. Methods: This monocentric, real-world study included 255 adult patients with pMMR/MSS mCRC who underwent routine comprehensive genomic profiling using the FoundationOne® Liquid CDx assay. bTMB was quantified in mutations per megabase (mut/Mb), and patients were classified into bTMB-low and bTMB-high groups using the cohort median. The primary endpoint was overall survival (OS). Subgroup analyses, including stratification by RAS/BRAF mutation status, were descriptive. Results: The median bTMB was 5 mut/Mb. Patients in the bTMB-high group had an increased risk of death compared with those in the bTMB-low group (hazard ratio (HR) 1.88). The adverse prognostic effect for OS of high bTMB was more pronounced in patients with RAS mutant tumors (HR 2.32) than with RAS/BRAF wild-type tumors (HR 1.81), while no prognostic impact was observed in BRAFV600E mutant tumors (HR 0.90). bTMB was strongly correlated with ctDNA fraction (p < 0.0001). Conclusions: In routine clinical practice, elevated bTMB is associated with poor prognosis in pMMR/MSS mCRC, particularly in RAS mutant tumors. These results contrast with prior tissue-based studies and indicate that bTMB may reflect tumor burden and aggressive disease biology rather than tumor immunogenicity. Prospective studies integrating bTMB with ctDNA fraction, tumor burden metrics, and longitudinal molecular dynamics are warranted to refine its clinical utility.

Reproduction is a key life-history trait but often comes at the expense of somatic maintenance, including ageing and susceptibility to disease. While reproduction-immunity trade-offs have been experimentally demonstrated in the context of infectious diseases, whether reproduction similarly undermines susceptibility to tumours has remained unclear. Using the freshwater cnidarian Hydra oligactis, in which tumours arise spontaneously and reproductive effort can be experimentally modulated through food availability, we tested the possibility of a trade-off between reproduction and tumour dynamics. Higher reproductive effort increased the likelihood of tumour development, reduced the probability of remission and increased the likelihood of progression to advanced stages. Resource availability modulated the strength of the trade-off in terms of tumour risk and remission, whereas tumour severity was determined solely by reproductive effort. Together, these findings provide rare empirical support for a trade-off between reproduction and tumour dynamics, demonstrating that reproductive investment compromises both tumour prevention and control and that its expression can be shaped by environmental conditions. More broadly, they suggest that cancer susceptibility in more complex lineages may instead reflect evolutionary trade-offs that prioritize reproduction over somatic maintenance, helping illustrate one mechanism by which evolutionary trade-offs contribute to the persistence of cancer and to variation in susceptibility across taxa.

Aging, and by extension age-related diseases, has traditionally been understood through classical evolutionary genetic models, such as the mutation accumulation and antagonistic pleiotropy theories. However, these frameworks primarily focus on the declining efficacy of organismal-level selection against mutations with deleterious effects in late life. Here, we propose a novel hypothesis: many chronic diseases associated with aging may emerge, at least in part, as a result of selection acting at lower organizational levels, including non-replicative biological entities, enabled by the relaxation of selective pressures that constrained within-organism evolutionary processes in early life. This hypothesis is built on the recently proposed concept of selection for function that extends the evolutionary process to non-replicative entities. While Darwinian selection acting at the organismal level strongly constrains within-organism evolution during an organism's reproductive lifespan, these constraints weaken with age. As a consequence, lower-level non-replicative entities, such as benign and malignant tumors, atherosclerotic plaques, and neurodegenerative aggregates, may experience a form of selection that favors those with increased stability, organization, and long-term persistence, sometimes at the cost to host fitness. These entities do not evolve via long-term differential reproduction, but rather certain configurations of their structure persist preferentially over others due to environmental constraints, microenvironmental selection, and internal stabilization mechanisms. Understanding aging through the lens of selection for function at the level of internal non-replicative entities provides new insights into the evolution of chronic diseases and opens novel therapeutic avenues aimed at disrupting internal functional organization, rather than merely targeting cellular proliferation/abnormalities or disease symptoms.

BackgroundLi-Fraumeni syndrome (LFS) predisposes individuals to a wide range of cancers from childhood onwards, underscoring the crucial need for accurate interpretation of germlineTP53variants for optimal clinical management of patients and families. Several unclassified variants, particularly those potentially affecting splicing, require specialised testing. One such example is the NM_000546.6:c.1101-2A>C (rs587781664) variant, located at the splice acceptor site of the last intron ofTP53, identified in a female patient with breast cancer diagnosed in her 20s.MethodsTo interpret this variant, which has been classified as a variant of uncertain significance (VUS), we developed specific assays including a p53 functional assay, RT-QMPSF, Splice and Expression Analyses by exon Ligation and High-Throughput Sequencing and long RT-droplet digital PCR.ResultsWe demonstrated a loss of p53 transcriptional activity, and a half reduction in TP53 mRNA expression. Additionally, we detected the use of a novel alternative last exon downstream of exon 11, which we have named exon 12. This transcript, typically detectable at low levels in most individuals, was found to be more highly expressed in the c.1101-2A>C carrier, predominantly transcribed from the mutant allele due to the disruption of the splice acceptor site in intron 10.ConclusionBy combining these approaches, we successfully reclassified this intronic VUS as ‘pathogenic’, enabling appropriate genetic counselling for the patient and her family. Additionally, we identified a novel TP53 alternative transcript that is expressed in both physiological and pathological contexts, with heightened expression in the patient with LFS. This discovery provides a basis for further investigation into the role of TP53 isoforms in LFS oncogenesis.

BACKGROUND:Women carrying a germline BRCA1 or BRCA2 mutation (gBRCAm) have a 70 % lifetime risk of breast cancer (BC). Aromatase inhibitors (AI) decrease BC incidence in high-risk populations but have not been specifically assessed in gBRCAm carriers. METHODS:LIBER was a randomized, double-blind, placebo-controlled, phase III trial. Post-menopausal women aged between 40 and 70 years carrying a gBRCAm were randomly allocated either 5 years of letrozole (2.5 mg/day) or placebo. Women with prior BC in remission for more than 5 years ago were eligible to assess the risk of second BC. Randomization was stratified by type of gBRCAm (BRCA1 versus BRCA2), previous bilateral oophorectomy, and prior BC. The primary endpoint was the 5-year incidence of invasive BC. Safety and quality of life were analyzed. RESULTS:Between 2008 and 2013, 170 women were randomized: 86 to placebo and 84 to letrozole. At 5 years, treatment adherence was 73.5 % with placebo and 76.7 % with letrozole. After a median follow-up of 72.7 months (95 % CI 71.5-78.5), the 5-year incidence of invasive BC was 13.1 % with placebo and 7.8 % with letrozole: hazard ratio, 0.70 (95 % CI 0.29-1.66), p = 0.416. Safety events and quality of life did not statistically differ in the arm. CONCLUSION:Due to the underpowered nature of the trial and the observed trend, it cannot be ruled out that using AI to prevent invasive breast cancer could be effective for BRCA1/2 carriers overall, or for specific subgroups within a larger sample size. Further randomised controlled trials are needed to determine the potential benefits of AI for gBRCA1/2m carriers.

The incidence of early-onset breast cancer (EOBC) has recently been shown to be increasing over time in the US and the UK. Using national cancer registries data including 229,352 BC cases, we show that the incidence rate of EOBC in France increased steadily from 1990 to 2023, rising from 16.1 (95 % CI: 14.7-17.8) to 26.3 (95 % CI: 20.7-33.3) and from 98.7 (95 % CI: 93.8-103.7) to 131.2 (95 % CI: 115.8-148.7) per 100,000 person-years in women aged 30 and 40 years, respectively. This population-based study confirms that the incidence of EOBC is increasing over time in Western countries. Further research is needed to explain this trend, which may have implications for prevention and screening strategies.

Current cancer therapies often fail due to tumor heterogeneity and rapid resistance evolution. A new evolutionary framework, 'selection for function,' proposes that tumor progression is driven by group phenotypic composition (GPC) and its interaction with the microenvironment, not by individual cell traits. This perspective opens new therapeutic avenues: targeting the tumor's functional networks rather than individual cells. Real-time tracking of GPC changes could inform adaptive treatments, delaying progression and resistance. By integrating evolutionary and ecological principles with conventional therapies, this strategy aims to transform cancer from a fatal to a manageable chronic disease. Crucially, it does not necessarily require new drugs but offers a way to repurpose existing therapies to impair a tumor's evolutionary potential. By steering tumor evolution toward less aggressive states, this approach could improve prognosis and long-term patient survival compared to current methods. We argue that leveraging GPC dynamics represents a critical, yet underexplored, opportunity in oncology.

Circulating tumor DNA (ctDNA) analysis offers a non-invasive approach to molecular profiling. While RAS mutations are well-established predictive biomarkers in metastatic colorectal cancer (mCRC), the prognostic value of their variant allele frequency (VAF) remains unclear. We retrospectively analyzed individual patient data with mCRC who underwent ctDNA testing using the FoundationOne® Liquid CDx assay. The primary objective was to determine the optimal RAS VAF cutoff for overall survival (OS) prognostication. Between November 2020 and July 2024, 282 patients were enrolled. Among 265 eligible patients, 134 (50.6%) were ctRAS mutant, 25 (9.4%) ctBRAFV600E mutant, and 106 (40.0%) were ctRAS/BRAF wild-type. A RAS VAF threshold of 5% yielded the highest prognostic discrimination for OS (HR = 2.41; 95% CI 1.65–3.55; p < 0.0001; C-index = 0.601). ctRAS-high mutant tumors (VAF ≥ 5%) were associated with synchronous metastatic disease, multiple metastatic sites, higher blood tumor mutational burden, and elevated tumor fraction. ctRAS-low mutant tumors (VAF < 5%) were more frequently metachronous, presented with a single metastatic site, and showed liver involvement. High RAS VAF in ctDNA is a strong and independent prognostic marker for OS in mCRC. Quantitative ctDNA profiling may enhance risk stratification and guide personalized management strategies.

Kabuki syndrome type 1 (KS1) is a monogenic disorder arising from pathogenic variants within KMT2D and characterized by syndromic neurodevelopmental delay. We report the retrospective identification of a causative AluY insertion within KMT2D in a genetically unsolved individual with typical KS1 features, after identification of a DNA methylation signature. This is the first documentation of Alu insertion as a molecular mechanism responsible for KS1. This study emphasizes the need for reanalyzing inconclusive sequencing data in individuals with gene-specific phenotypes and reinforces episignature as a reliable diagnostic tool when NGS approaches fail to provide conclusive results in individuals with rare diseases.

Background: Women with a familial predisposition to breast cancer (BC) are offered screening at earlier ages and more frequently than women from the general population. Methods: We evaluated the effect of screening mammography in 1552 BC cases with a hereditary predisposition to BC unexplained by BRCA1 or BRCA2 and 1363 unrelated controls. Participants reported their lifetime mammography exposures in a detailed questionnaire. Germline rare deleterious or predicted deleterious variants (D-PDVs) in 113 DNA repair genes were investigated in 82.5% of the women and classified according to the strength of their association with BC. Genes with an odds ratio (OR) < 0.9 was assigned to the Gene Group “Reduced”, those with OR ≥ 0.9 and ≤1.1 to Group “Independent”, and those with OR > 1.1 to Group “Increased”. Results: Overall, having been exposed to mammograms (never vs. ever) was not associated with BC risk. However, an increase in BC risk of 4% (95% CI: 1–6%) per additional exposure was found under the assumption of linearity. When grouped according to D-PDV carrier status, mammograms doubled the BC risk of women carrying a D-PDV in Group “Reduced”, as compared to those carrying a D-PDV in Group “Increased”. Conclusions: Our study is the first to investigate the joint effect of mammogram exposure and variants in DNA repair genes other than BRCA1 and BRCA2 in women at high risk of BC; therefore, further studies are needed to verify our findings. Even though mammographic screening reduces the risk of mortality from BC, the identification of populations that are more or less susceptible to ionizing radiation may be clinically relevant.

IntroductionAccurate identification and characterization of Large Genomic Rearrangements (LGR), especially duplications, are crucial for precise diagnosis and risk assessment. In this report, we characterized an intragenic duplication breakpoint of PALB2 to determine its pathogenicity significance.MethodsA 52-year-old female with triple-negative breast cancer was diagnosed with a novel PALB2 LGR. An efficient and accurate methodology was applied, combining long-read sequencing and transcript analysis for the rapid characterization of the duplication.ResultsDuplication of exons 5 and 6 of PALB2 was validated by transcript analysis. Long-read sequencing enabled the localization of breakpoints within Alu elements, providing insights into the mechanism of duplication via non-allelic homologous recombination.ConclusionUsing our combined methodology, we reclassified the PALB2 duplication as a pathogenic variant. This reclassification suggests a possible causative link between this specific genetic alteration and the aggressive phenotype of the patient.

BACKGROUND:Poly (ADP ribose) polymerase inhibitors (PARPis) are a treatment option for patients with advanced high-grade serous or endometrioid ovarian carcinoma (OC). Recent guidelines have clarified how homologous recombination deficiency (HRD) may influence treatment decision-making in this setting. As a result, numerous companion diagnostic assays (CDx) have been developed to identify HRD. However, the optimal HRD testing strategy is an area of debate. Moreover, recently published clinical and translational data may impact how HRD status may be used to identify patients likely to benefit from PARPi use. We aimed to extensively compare available HRD CDx and establish a worldwide expert consensus on HRD testing in primary and recurrent OC. METHODS:A group of 99 global experts from 31 different countries was formed. Using a modified Delphi process, the experts aimed to establish consensus statements based on a systematic literature search and CDx information sought from investigators, companies and/or publications. RESULTS:Technical information, including analytical and clinical validation, were obtained from 14 of 15 available HRD CDx (7 academic; 7 commercial). Consensus was reached on 36 statements encompassing the following topics: 1) the predictive impact of HRD status on PARPi use in primary and recurrent OC; 2) analytical and clinical validation requirements of HRD CDx; 3) resource-stratified HRD testing; and 4) how future CDx may include additional approaches to help address unmet testing needs. CONCLUSION:This manuscript provides detailed information on currently available HRD CDx and up-to-date guidance from global experts on HRD testing in patients with primary and recurrent OC.

187 Background: Addressing tumor heterogeneity is one of the main advantage of liquid biopsy over tissue biopsy, as liquid biopsy is likely to better reflect the global molecular profile (primary tumor site and metastatic disease). Variant Allele Frequency (VAF) represents the fraction of sequencing reads in which a variant is observed. The aim was to evaluate the prognostic value of circulating tumor (ct) VAF for KRAS and NRAS genes in patients with ctRAS mutant metastatic colorectal cancer (MCRC). Methods: Circulating comprehensive genomic profiling using FoundationOne Liquid CDx (FO-Liq) was proposed to patients with histologically proven or highly suspected solid tumor whatever treatment line. FO-Liq is a next generation sequencing panel of 310 cancer related genes and 3 genomic signatures (blood tumor mutational burden (bTMB), microsatellite instability (MSI) and tumor fraction (TF)). The optimal threshold for ctVAF was determined by calculating Harrell’s C discrimination index extended for survival data. The primary endpoint was overall survival (OS). Results: From October 2020 to June 2023, 740 patients were screened for circulating molecular profiling. In the colorectal cohort (N=201), 198 (98.5%) patients had metastatic disease (ctRAS/BRAF wild-type, N=76 (38.4%) ; ctRAS mutant, N=106 (53.5%) and ctBRAF V600E mutant, N=16 (8.1%)). The optimal threshold for ctVAF RAS was 5% (C-index 0.67, 95% CI 0.62-0.73 ; P<0.0001). Among patients with ctRAS mutant MCRC, 43 (40.6%) were ctRAS mutant-Low (VAF RAS <5%) and 63 (59.4%) were ctRAS mutant-High (VAF RAS ≥5%). Median follow-up was 18.5 months (95% CI 15.3-34.5). There was a significant increase in the the risk of death for RAS mutant-High compared to RAS mutant-Low (HR 2.81, 95% CI 1.70-4.63; P<0.001). Patients with RAS mutant-low variants had the same prognosis that RAS/BRAF wild-type profile (HR 1.22 ; P=0.573), and patients with RAS mutant-high variants had the same prognosis that BRAF mutant profile (HR 0.82, P=0.563). The factors associated with RAS mutant-High profile were : bTMB-High, TF-High, RAS G12A and G13D variants. MAP kinase, TGFb and Wnt signaling pathways and BRCA1-2 genes were more frequently altered in patients with ctRAS mutant-High tumors. We observed a transient decrease of VAF RAS in second-line setting. Conclusions: The circulating VAF of RAS genes enables to split RAS mutant-Low (favorable prognosis similar to RAS/BRAF wild-type) from RAS mutant-High (poorer prognosis similar to BRAF mutant) metastatic colorectal cancer. These results provide further insights into prognostication and therapeutic strategies in patients with RAS mutant metastatic colorectal cancer.

ABSTRACTWhile it is recognised that most, if not all, multicellular organisms harbour neoplastic processes within their bodies, the timing of when these undesirable cell proliferations are most likely to occur and progress throughout the organism's lifetime remains only partially documented. Due to the different mechanisms implicated in tumourigenesis, it is highly unlikely that this probability remains constant at all times and stages of life. In this article, we summarise what is known about this variation, considering the roles of age, season and circadian rhythm. While most studies requiring that level of detail be done on humans, we also review available evidence in other animal species. For each of these timescales, we identify mechanisms or biological functions shaping the variation. When possible, we show that evolutionary processes likely played a role, either directly to regulate the cancer risk or indirectly through trade‐offs. We find that neoplastic risk varies with age in a more complex way than predicted by early epidemiological models: rather than resulting from mutations alone, tumour development is dictated by tissue‐ and age‐specific processes. Similarly, the seasonal cycle can be associated with risk variation in some species with life‐history events such as sexual competition or mating being timed according to the season. Lastly, we show that the circadian cycle influences tumourigenesis in physiological, pathological and therapeutic contexts. We also highlight two biological functions at the core of these variations across our three timescales: immunity and metabolism. Finally, we show that our understanding of the entanglement between tumourigenic processes and biological cycles is constrained by the limited number of species for which we have extensive data. Improving our knowledge of the periods of vulnerability to the onset and/or progression of (malignant) tumours is a key issue that deserves further investigation, as it is key to successful cancer prevention strategies.