Search Results (624)

Background: Oral leukoplakia is a clinically important oral potentially malignant disorder with variable risk of progression to oral squamous cell carcinoma. Histopathological grading of oral epithelial dysplasia remains the primary method for risk assessment; however, its predictive accuracy is limited by sampling variability, lesion heterogeneity, and interobserver variation. DNA aneuploidy and abnormal DNA ploidy status have therefore been investigated as objective biomarkers of genomic instability and potential predictors of malignant transformation. Aim: This narrative review evaluates whether DNA aneuploidy or abnormal DNA ploidy status predicts malignant transformation of oral leukoplakia to oral squamous cell carcinoma compared with diploid DNA status, and whether DNA ploidy should be interpreted as a stand-alone prognostic marker or as part of combined risk-assessment models. Materials and Methods: A structured PubMed/MEDLINE search (last performed on 12 July 2026) identified 162 records using terms related to oral leukoplakia, oral potentially malignant disorders, DNA ploidy, DNA aneuploidy, cytometry, malignant transformation, and oral squamous cell carcinoma. After screening and full-text eligibility assessment, 45 studies were included and organised according to their evidential role as core prognostic studies, PVL-specific subgroup evidence, and supporting/background evidence addressing diagnostic relevance, dysplasia correlation, treatment monitoring, genomic instability, and methodological development. Results: Most core prognostic studies showed that DNA aneuploidy, abnormal DNA content, or chromosomal instability was associated with increased malignant transformation risk compared with diploid or non-aneuploid status. Several studies reported higher transformation rates, hazard ratios, or improved prediction when DNA ploidy was combined with dysplasia grading, lesion site, clinical heterogeneity, or other biomarkers. However, predictive performance varied across studies, and DNA ploidy alone often showed modest sensitivity, specificity, or positive predictive value. Diploid or non-aneuploid status appeared more useful for identifying lower-risk lesions, although it did not completely exclude malignant transformation. PVL evidence suggested frequent aneuploidy and aggressive genomic behaviour, but DNA ploidy appeared less reliable for discriminating risk within PVL. Conclusions: DNA aneuploidy and abnormal DNA ploidy status are meaningful markers of genomic instability and are associated with increased malignant transformation risk in oral leukoplakia. However, when used alone, DNA ploidy often shows only modest predictive performance, and prediction improves consistently when it is combined with dysplasia grading and other clinicopathological factors. Their strongest clinical value is therefore as adjunctive biomarkers within combined clinicopathological and molecular risk models, rather than as stand-alone replacements for histopathological assessment; routine clinical implementation is not yet supported by the current evidence. Full article

The Structural Maintenance of Chromosomes 5/6 (SMC5/6) complex is a key regulator of genome stability that participates in the recognition, stabilization, and processing of DNA intermediates generated during DNA replication and homologous recombination. Recent advances in structural and biochemical studies have revealed the architecture of the SMC5/6 complex and elucidated the molecular mechanisms by which ATPase activity, DNA-binding modules, and SUMO-and ubiquitin-mediated regulatory pathways cooperate to maintain genome integrity. Extensive evidence has further demonstrated that SMC5/6 functions as a broad-spectrum antiviral restriction factor by recognizing and silencing episomal viral genomes, whereas diverse viruses have evolved strategies to evade or counteract its activity. In addition, dysfunction of the SMC5/6 complex has been associated with cancer, developmental disorders, and genome instability syndromes. This review summarizes recent advances in the structure, molecular mechanisms, antiviral functions, and disease relevance of the SMC5/6 complex, providing a basis for a deeper understanding of its diverse biological functions and potential applications. Full article

Induced pluripotent stem cells (iPSCs) are prone to genomic instability during prolonged culture, with recurrent chromosomal aberrations conferring selective advantages. Replication stress is a major driver of this instability, yet the repertoire of replication stress-sensitive loci in iPSCs remains largely unexplored. Here, we mapped aphidicolin-sensitive fragile sites (asFS) in three independent iPSC lines using classical cytogenetic break analysis combined with Monte Carlo simulation and MiDAS mapping directly on banded metaphase chromosomes. We identified 28 asFS, which segregated into a highly active Major cluster (8 sites, accounting for 59% of breaks among asFS) and a less active Minor cluster (20 sites). Five universal asFS (9p21, 6q25-26, 20p11-12, 10q22, Xq25) were present in all three lines, representing a fragility signature associated with the pluripotent state, with Xq25 shifting into the Major cluster after correction for X chromosome dosage. Minor asFS showed preferential co-localization with physical breakpoints or minimal overlapping regions of recurrent culture-acquired aberrations, including 20q11.21 (BCL2L1), 1q32 (MDM4), 8q24 (MYC), 17q21 (WNT3-WNT9B), and 18q21 (DCC/FRA18B). MiDAS mapping validated most asFS and revealed additional replication stress-sensitive loci in pericentromeric and subtelomeric regions that are difficult to score by conventional G-banding. Comparison with fragile site maps from other cell types revealed that the iPSC asFS repertoire is distinct in rank order and relative activity, characteristic of the pluripotent state. Collectively, our findings indicate that the asFS repertoire in iPSCs is hierarchically organized into a stable universal core and a variable peripheral component, and suggest that Minor asFS may contribute to, or be associated with, the genesis of culture-acquired rearrangements. This work provides a framework for understanding how replication stress and clonal selection shape the mutational landscape of pluripotent stem cells. Full article

Background/Objectives: Breast cancer (BC) is the most frequently diagnosed malignancy and a leading cause of cancer-related mortality in women worldwide. This disease is highly heterogeneous and dynamic, and chromosomal instability (CIN) plays a key role in the acquisition of these traits by generating genetic diversity that promotes tumor adaptation and influences therapeutic response and prognosis. Although several methods have been developed to quantify CIN, they are not readily applicable to human tumors and are limited in resolution, hindering a comprehensive understanding of intratumoral heterogeneity. In this study, we aimed to quantify CIN levels and clonal heterogeneity (CH) in HER2-positive (HER2+) and triple-negative (TNBC) breast cancer using single-cell RNA sequencing (scRNA-seq) data. Methods: We analyzed publicly available scRNA-seq data from HER2+ and TNBC tumors and non-malignant controls. CIN was scored at single-cell resolution using transcriptomic signatures, clonal heterogeneity was estimated from single-cell diversity metrics, and copy number alterations were inferred computationally. Differential expression and functional enrichment analyses were performed between cells with very low and extreme CIN levels, with key comparisons confirmed at the patient level. Results: Our analyses revealed pronounced intra- and intertumoral heterogeneity, with higher CIN levels in TNBC than in HER2+ and control samples. Genes differentially expressed in cells with extreme CIN values were mainly involved in cell division and related processes, and included candidate biomarkers not previously reported in this context. Our findings suggest a positive but statistically non-significant trend was observed between CIN and CH. Conclusions: Single-cell approaches such as scRNA-seq provide a powerful framework to elucidate CIN-related mechanisms and to identify potential biomarkers of BC aggressiveness and prognosis, supporting their further application in the study of intratumoral heterogeneity. Full article

Background/Objectives: The domestic yak (Bos grunniens) is a livestock species of major relevance in high-altitude environments and an important model for studying adaptation and reproductive isolation within Bovini. Despite its close phylogenetic relationship with cattle (Bos taurus), yak × cattle hybrids show a marked sex-biased fertility pattern, with fertile females and generally sterile F1 males, suggesting that subtle chromosomal or genomic differences may underlie post-zygotic reproductive barriers. In this study, we performed a cytogenetic characterization of eight adult yak bulls imported and reared in Central Italy using conventional and molecular cytogenetic approaches. Results: GTG-, RBG-, RBA- and CBA-banding confirmed the yak diploid number as 2n = 60 and the fundamental number as NF = 62, with banding patterns highly comparable to the standardized cattle karyotype. CBA-banding showed an X chromosome lacking evident constitutive heterochromatin and a Y chromosome with distal C-positive blocks. Chromosome instability was low, with 3.75% abnormal metaphases, mainly represented by chromatid and iso-chromatid breaks, while the mean sister chromatid exchange (SCE) rate was 5.19 ± 2.14 per cell. Sequential Ag-NOR/RBA staining localized nucleolar organizer regions (NORs) at the telomeres of autosomes 2, 3, 4, 11 and 25, as in cattle. Zoo-FISH using bovine chromosome paints for X, Y, 5 and 15 showed complete hybridization to the corresponding yak chromosomes, and BAC-FISH mapped the Y-linked ZFY and SRY genes to positions homologous to those reported in cattle. A comparative bioinformatics analysis of available yak genome assemblies confirmed the overall genome-wide correspondence with cattle, while revealing chromosome orientation issues and small local inconsistencies that may be relevant for comparative mapping and probe design. Conclusions: Overall, at the resolution tested, these findings support broad macrostructural conservation of yak and cattle karyotypes and provide cytogenetic reference data for yak populations reared outside of their traditional range. The persistence of F1 male sterility despite this large-scale chromosomal conservation suggests that fine-scale sex chromosome differences, particularly involving pseudoautosomal regions, recombination boundaries, or heterochromatin organization, may deserve targeted investigation. Full article

Paclitaxel (PTX) is a core first-line chemotherapeutic agent used to treat a broad spectrum of cancers, which remain leading causes of death worldwide. However, the emergence of intrinsic and acquired resistance critically contributes to chemotherapy failure, thereby promoting tumor recurrence and metastasis and resulting in a poor prognosis. PTX resistance is a complex biological process driven by multiple factors and cross-regulated signaling pathways. It encompasses a wide variety of mechanisms, including aberrations in microtubules and related proteins; changes in mitotic systems and chromosomal instability (CIN); epigenetic modifications including ncRNA regulation, DNA methylation, and histone modification; enhanced drug efflux and dysregulation of proliferation and apoptotic signaling pathways; enhanced protective autophagy; metabolic reprogramming; cell plasticity (increased EMT and cancer cell stemness); TME remodeling; and immune regulation. This review systematically examines the core molecular mechanisms of PTX resistance, summarizes cutting-edge strategies to reverse chemoresistance and their clinical translation, and discusses current challenges and future directions, thereby providing a theoretical framework for optimizing PTX-based regimens and overcoming clinical resistance. Full article

Background/Objectives: The base excision repair (BER) pathway repairs oxidative DNA damage, a common and detrimental form of damage to the genome. Although biochemical steps in BER have been well defined, little is understood about how the pathway is regulated. Such regulation is critical, as cells must respond rapidly to DNA damage while avoiding aberrant activation of repair proteins that can produce DNA damage as intermediates in the repair pathway. Indeed, overexpression of the human BER protein NTHL1, a DNA N-glycosylase, can cause genomic instability and early cellular hallmarks of cancer. Methods: We developed a Saccharomyces cerevisiae model to explore how overexpression of NTHL1 may impair cellular function. Results: Overexpression of Ntg1, the budding yeast orthologue of NTHL1, impairs cell growth. To dissect mechanisms underlying this growth defect, we overexpressed either wild-type Ntg1 or a catalytically inactive variant of Ntg1 (ntg1_catdead). Consistent with results obtained for NTHL1, both variants of Ntg1 impair cell growth, but only the wild-type protein causes accumulation of double-strand breaks and chromosome loss. We screened a panel of DNA repair mutants for resistance/sensitivity to overexpression of wild-type Ntg1 or ntg1_catdead. This analysis identified several cellular pathways that protect cells from Ntg1-induced damage, providing insight into the interplay between DNA repair pathways. Finally, we identified a link to SUMOylation and probed into how this post-translational modification could contribute to regulation of Ntg1 function. Conclusions: This study describes a budding yeast system to understand how cells regulate and respond to dysregulation of the BER pathway. Full article

Bladder cancer (BC) is a common urological malignancy that lacks the non-invasive biomarkers that would make it suitable for early diagnosis. Human alpha-satellite DNA (hASAT) is a tandemly repeated centromeric/pericentromeric DNA family associated with chromosomal stability and cancer-related genomic instability. We quantified extracellular hASAT (ec-hASAT) in plasma circulating cell-free DNA by nanoplate-based digital PCR in a pilot cohort including 29 BC-negative samples, 10 patients with non-muscle-invasive BC (NMIBC), and 7 patients with muscle-invasive BC (MIBC). Plasma ec-hASAT copy number was higher in patients with BC than in the BC-negative group (Mann–Whitney U test, p = 6.61 × 10⁻⁷). BC-negative samples ranged from 225 to 11,864 copies/µL plasma, whereas BC samples ranged from 1138 to 16,097 copies/µL plasma. ROC analysis yielded an AUC of 0.944 for discriminating BC from BC-negative samples. At an exploratory threshold of 2000 copies/µL plasma, sensitivity was 94.1% (16/17; exact 95% CI, 71.3–99.9%) and specificity was 89.7% (26/29; exact 95% CI, 72.6–97.8%). These preliminary data support plasma ec-hASAT as a candidate minimally invasive biomarker for BC detection, including NMIBC, and justify validation in larger prospective cohorts. Full article

The exponential rise in global plastic production has resulted in the widespread environmental dissemination of micro- and nanoplastics (MNPs) across air, water, and biological systems. Inhalation of airborne MNPs represents a biologically plausible pathway of pulmonary exposure, particularly within indoor and occupational environments. Experimental evidence indicates that inhaled MNPs deposit within distal lung compartments, where their small aerodynamic diameter and surface reactivity may favor cellular uptake, oxidative stress induction, inflammatory activation, and prolonged biopersistence. Experimental studies further indicate that MNP exposure may induce DNA damage, chromosomal instability, and the dysregulation of signaling pathways involved in genomic integrity, thereby providing additional mechanistic support for their potential role in carcinogenesis. Chronic redox imbalance, macrophage dysfunction, inflammasome activation, epithelial–mesenchymal transition, and dysregulated cell adhesion collectively resemble mechanisms implicated in inflammation-associated carcinogenesis. Emerging in vitro and in vivo data further suggest that nanoplastics may function as tumor promoters or co-carcinogenic modifiers, particularly under chronic low-dose exposure or in combination with other airborne toxicants. However, human epidemiological evidence remains limited, and causality has not been established. This review synthesizes current mechanistic evidence regarding inhaled MNPs as potential modifiers of lung carcinogenesis, compares them with established inhaled carcinogens, and outlines critical research priorities necessary to clarify exposure–response relationships and clinical relevance. Current evidence supports biological plausibility rather than confirmed carcinogenic classification. Full article

Sarcomas with Murine Double Minute 2 (MDM2) amplification are considered potential candidates for MDM2-targeted therapy. However, the limited efficacy of MDM2 inhibitor monotherapy suggests that additional biological factors may influence tumor behavior and prognosis. This study investigated the relationship between MDM2 expression and the Complexity Index in SARComas (CINSARC) transcriptomic signature, a gene expression signature that reflects cell division and chromosomal instability in soft tissue sarcomas. In the public GSE21050 dataset comprising 310 soft tissue sarcomas, the MDM2-low/CINSARC-low subgroup showed the most favorable metastasis-free survival, whereas the MDM2-high/CINSARC-low subgroup had an unfavorable metastasis-free survival comparable to that of the MDM2-high/CINSARC-high group. Among the representative genes in the 12q13-15 region, fibroblast growth factor receptor substrate 2 (FRS2) showed a strong positive correlation with MDM2 expression, but no significant correlation with CINSARC, suggesting an association independent of proliferative capacity. These findings suggest that proliferation-based risk assessment alone may underestimate the metastatic risk of a subset of MDM2-high sarcomas, and FRS2 may present a biologically relevant marker of aggressive behavior independent of tumor proliferation. Full article

Gliomas are the most common and aggressive primary brain tumours, with glioblastoma (GB) exhibiting a poor prognosis and limited therapeutic response. Dysregulation of intracellular ion homeostasis, particularly Ca²⁺ signalling, has emerged as a key contributor to glioma progression. The transmembrane BAX inhibitor motif-containing (TMBIM) protein family regulates intracellular Ca²⁺ flux and cell survival; however, their role in glioma remains incompletely understood. Gene expression and clinical data from TCGA, CGGA, and Rembrandt cohorts were analysed to assess the association between TMBIM1-6 expression, tumour grade, and patient survival. Correlation analyses identified TMBIM-associated gene networks, followed by functional enrichment to characterise underlying biological processes and molecular functions. The TMBIM family members segregated into two distinct groups with opposing clinical associations. TMBIM1, TMBIM4, and TMBIM6 were upregulated and associated with poor survival, whereas TMBIM2, TMBIM3, and TMBIM5 were downregulated and associated with increased survival. Functional enrichment analyses revealed two conserved gene expression programmes: TMBIM1/4/6 are linked to membrane trafficking, metabolic and bioenergetic adaptation, while TMBIM2/3/5 are associated with cell cycle regulation and chromosomal instability. These findings uncover a previously unrecognised functional divergence within the TMBIM family in glioma. This bipartite organisation highlights TMBIM proteins as potential prognostic markers and suggests that selective targeting of specific TMBIM subgroups may improve therapeutic strategies. Full article

Oocyte aging is a conserved biological process that limits reproductive success across animal taxa. While most research has focused on mammalian systems, particularly humans, comparative studies reveal both shared molecular mechanisms and lineage-specific adaptations that shape oocyte longevity. Here, we synthesise current knowledge on chromosomal instability, mitochondrial dysfunction, proteostasis collapse and epigenetic alterations, integrating insights from insects, nematodes and vertebrates. We argue that these phenomena should not be viewed as independent hallmarks of reproductive aging but rather as interconnected manifestations of a progressive decline in cellular quality control networks. By comparing taxa, we identify both conserved vulnerabilities, including cohesin loss, mitochondrial deterioration and genome instability, and lineage-specific adaptations that mitigate their effects. We further propose the hypothesis that biomolecular condensates, including the Balbiani body, nuage and recently described endolysosomal assemblies, may function as higher-order organizational hubs coordinating mitochondrial quality control, proteostasis and genome defence. This perspective provides a unifying framework for understanding oocyte aging as a systems-level process and highlights new directions for future studies of reproductive longevity. Full article

Background/Objectives: Glioblastoma remains the most aggressive and lethal form of brain cancer, with no effective cure to date. The molecular mechanisms sustaining its development and relentless proliferation are still not fully understood. SETMAR, a protein lysine methyltransferase involved in various DNA repair and chromatin processes, has been reported as dysregulated in several cancers, including glioblastoma. Interestingly, S-SETMAR, a shorter isoform of SETMAR, has been suggested to antagonize the oncogenic properties of the full-length protein. Here, we explored the cellular and molecular consequences of S-SETMAR overexpression in glioblastoma cells. Methods: We compared native glioblastoma cells (8MGBA) with a recombinant 8MGBA line stably over-expressing αS-SETMAR, a stable form of S-SETMAR, using complementary cellular and molecular approaches. Results: Overexpression of αS-SETMAR markedly prolonged the cell cycle duration (from 27 to 37 h), leading to a significant decrease in cell proliferation. Unexpectedly, αS-SETMAR triggered genomic alterations characterized by an increased DNA content and extensive chromosomal instability, including aneuploidy, chromoanasynthesis-like rearrangements, and tripolar mitoses. Moreover, αS-SETMAR-expressing cells displayed heightened sensitivity to stress conditions mimicking chemotherapy and radiotherapy, resulting in increased apoptosis. Conclusions: Our findings identify αS-SETMAR as a dual modulator of glioblastoma cell fate—simultaneously slowing proliferation and promoting chromosomal instability while enhancing vulnerability to genotoxic stress. These results suggest that αS-SETMAR could serve as both a prognostic marker and a potential therapeutic tool in glioblastoma management. Full article

Chromosomal instability (CIN) arising from mitotic errors is a hallmark of cancer progression, yet how specific spindle assembly factors are co-opted to support aggressive tumor phenotypes remains incompletely understood. Hepatoma Upregulated Protein (HURP/DLGAP5), a Ran-regulated microtubule-associated protein essential for kinetochore fiber stabilization and chromosome congression, is frequently overexpressed in aggressive cancers. Here, we investigated HURP’s role across a breast cancer metastatic gradient—immortalized MCF10A, the low-metastatic luminal T47D, and the highly metastatic triple-negative MDA-MB-231 cell lines—integrating quantitative spindle analysis, kinetochore tension measurements, spindle checkpoint profiling, migration dynamics, and three-dimensional spheroid modeling. We show that total HURP protein levels increase with metastatic potential, yet spindle-bound HURP is paradoxically reduced in MDA-MB-231 cells, indicating cytoplasmic mislocalization despite increased total protein levels. HURP silencing induced cell-line-specific defects: moderate disorganization and misorientation in MCF10A and T47D cells, but catastrophic spindle collapse, apoptosis, and G2/M arrest in MDA-MB-231 cells. Mechanistically, HURP depletion disrupted the spindle-associated levels and distributions of TPX2, Aurora-A, and NuMA in a subtype-dependent manner, implicating HURP as a context-dependent stabilizer of this mitotic regulatory axis. HURP loss reduced interkinetochore tension in all cell lines, but only MCF10A and T47D cells mounted a proportional BubR1-dependent checkpoint response; MDA-MB-231 cells showed reduced checkpoint signaling, consistent with constitutive spindle assembly checkpoint (SAC) attenuation in triple-negative breast cancer. Beyond mitosis, HURP depletion impaired collective migration and converted MDA-MB-231 cells from super-diffusive, amoeboid-like motility to sub-diffusive behavior, while minimally affecting the less aggressive cell lines. HURP-depleted MDA-MB-231 spheroids were significantly larger, less compact, and less spherical than controls, linking spindle regulation to tissue-level architectural coherence. These findings establish HURP as a multifunctional regulator coordinating mitotic fidelity, migration plasticity, and tumor architecture in breast cancer, with a selective dependency in highly metastatic cells, positioning it as a promising therapeutic target for aggressive breast cancers. Full article

Background: Extrachromosomal DNA (ecDNA) amplification represents a distinct mechanism of genomic instability in cancer, increasingly recognized for its role in aggressive disease progression. This review examines how ecDNA drives tumour evolution and assesses its potential as both a prognostic marker and therapeutic target. Methods: The authors integrate findings from multiple detection platforms—including FISH, whole-genome sequencing, and specialized reconstruction algorithms—and present data across diverse cancer types; no preregistration is noted, and no animal studies are included. Results: ecDNA consists of circular, acentric DNA elements carrying high-copy oncogene amplifications (such as EGFR, MYC, MDM2, and CDK4). Unlike chromosomal DNA, ecDNA segregates unevenly during cell division, generating intratumoral heterogeneity, accelerating adaptation to selective pressures, and promoting resistance to therapy. Pan-cancer surveys summarized here reveal ecDNA in a significant subset of tumours, with particularly high frequencies in liposarcoma, glioblastoma, and HER2-positive breast cancer, and consistent associations with worse clinical outcomes. Conclusions: The authors conclude that ecDNA amplification serves as a credible adverse prognostic indicator and holds promise for refining risk stratification and guiding treatment strategies. However, they stress that clinical adoption remains constrained by the absence of standardized, scalable, and reproducible detection. Full article