The Journal of Pathology最新文献

Histiocytic neoplasms are rare haematologic diseases characterised by clonal expansions of cells with a monocyte, macrophage or dendritic cell phenotype. Their clinical manifestations are diverse, ranging from indolent lesions to aggressive systemic disease. Over recent decades, advances in genomic profiling have transformed the biological understanding of these conditions. The discovery of recurrent oncogenic mutations has reframed histiocytoses from primary inflammatory disorders to myeloid neoplasms, with a notable dependence on aberrant mitogen-activated protein kinase (MAPK) signalling. Novel genetic drivers continue to be uncovered, with many alterations correlating with distinct clinical and pathological phenotypes. Parallel studies have refined the understanding of disease ontogeny, demonstrating that diverse histiocytoses originate from haematopoietic stem/progenitor cells. In Langerhans cell histiocytosis, the differentiation stage of the mutated precursor cell is considered an important — but not the sole — determinant of disease extent and severity. Additional evidence suggests that specific clinical manifestations, such as neurodegenerative disease, may result from somatic mosaicism affecting tissue-resident macrophages derived from yolk sac progenitors. Collectively, these findings refine histiocytosis diagnosis, risk stratification, disease monitoring and treatment, with robust activity of kinase inhibitors in patients with severe or refractory disease. In this review, we synthesise recent genomic insights into histiocytosis development and variation, while addressing remaining questions and future directions. © 2026 The Author(s). The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Myotonic dystrophy type 1 (DM1) is a clinically challenging multisystem neuromuscular hereditary disorder, with generational increase in severity and earlier age at onset. It is caused by an unstable cytosine-thymine-guanine repeat expansion at the DMPK locus, accompanied by associated genetic and epigenetic modifications. While somatic mosaicism and meiotic instability are well established, to the best of our knowledge, no study has performed a genome-wide interrogation for global inherited instability. Performing whole-genome optical mapping, with sequence base-resolved structural variant verification, we examine global inherited genomic instability in an atypical paternally transmitted DM1 family presenting with a range of neurological manifestations, including early-onset Parkinson's disease (PD). While the juvenile-onset DM1 proband presented with a 10-fold repeat expansion with associated hypermethylation, her partially hypermethylated asymptomatic protomutation father transmitted a 1.8-fold contracted allele in the younger premutation sibling. Adult-onset symptomatic DM1 and PD phenotypic paternal aunts showed significant genome-wide copy number alteration, including PD-associated chr19 aneuploidy loss, with additional losses on chr16, 17, and 22. In the absence of potentially pathogenic de novo or maternally inherited structural variants, the proband presented with large paternally inherited aberrations impacting gene candidates CASC15, CBFA2T3, GPHN, H3F3A, SDK1, and SPAG16, with advanced global hypomethylation. Here we suggest that inherited genomic instability may contribute to phenotypic variability, including multi-neurological presentations and single-generation repeat expansion or contraction. By providing a landscape of inherited large structural variants, this single-family study expands knowledge of this broad and growing class of diseases. © 2026 The Author(s). The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Acquired lipodystrophy in the dermal white adipose tissue (DWAT) is an early phenotype of skin fibrosis, followed by the accumulation of extracellular matrix (ECM). Lipodystrophy syndromes are estimated to affect 1 in 20,000 people and are associated with metabolic comorbidities. Recently, we showed that fibrosis-associated lipodystrophy depended on sustained Wnt signaling, although the mechanism remains unclear. Transcriptomic profiling of mature dermal adipocytes in vivo revealed that Wnt activation downregulated the de novo lipogenesis (DNL) axis enzymes within 48 h. We further found that expression of fatty acid synthase (FASN), a key DNL enzyme, depends on sustained Wnt activation in vitro and in vivo. In a bleomycin model, and in human systemic sclerosis (< 1 year disease duration) and keloids, FASN was significantly downregulated. Notably, inhibition of FASN in mice during reversal of Wnt-induced fibrosis impaired the recovery of DWAT lipid content and ECM architecture. Collectively, these findings demonstrate that acquired lipodystrophy in skin fibrosis is mediated by a previously unrecognized role of the Wnt–DNL axis. These findings underscore the importance of this pathway in lipodystrophy and fibrosis and highlight its potential as a therapeutic target in skin fibrosis. © 2026 The Author(s). The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Tumor border configuration influences colorectal cancer (CRC) prognosis, yet its molecular determinants remain unclear and existing assessment criteria have faced challenges with reproducibility. We introduce the Tumor Invasive Border Index (TIBI), a novel and reproducible method that quantifies the proportion of tumor stroma and adipose tissue within a hotspot at the deepest point of invasion. TIBI was evaluated in two CRC cohorts (n = 1,100 and n = 776) and analyzed in relation to tumor and patient features. Molecular correlates of an infiltrative growth pattern were explored in The Cancer Genome Atlas (TCGA) CRC cohorts (n = 350), with key features validated independently. High TIBI, indicating an infiltrative border, was associated with advanced disease, tumor budding, lymphovascular invasion, and an immune microenvironment characterized by lower M1-like macrophage and granulocyte densities. High TIBI independently predicted higher CRC-specific mortality, with multivariable hazard ratios of 1.52 (95% CI 1.07–2.17) in cohort 1 and 2.45 (95% CI 1.37–4.37) in cohort 2. Molecular analysis revealed associations with mismatch repair proficiency, TP53 and KRAS mutations, MYC signaling downregulation, and epithelial-mesenchymal transition upregulation. L1CAM and DSG3 were among the genes showing high expression in infiltrative tumors. As experimental validation, we identified a CRC cell line with high expression of L1CAM and DSG3 and demonstrated that silencing them reduced invasion in vitro. A TIBI-associated gene signature also predicted infiltrative growth and adverse outcome in the TCGA gastric cancer cohort. These findings highlight molecular characteristics of tumor border configuration and establish TIBI as a clinically relevant tumor biomarker. © 2026 The Author(s). The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Gastrointestinal cancer is a global health problem. In the new 6th edition of the World Health Organization Classification of Tumours (WCT) of the Digestive System, updated evidence and guidance is provided for the aetiology, pathogenesis, diagnosis, classification, grading, staging and prognosis of these tumours. However, significant knowledge gaps remain, some of which are addressed in this review. To provide for a research framework to fill these knowledge gaps, we focused on precursor lesions and rare cancers, where the need for new evidence is most urgent. Areas with a need for further research are discussed for neoplastic precursors of the oesophagus (squamous epithelium), stomach (gastric dysplasia and adenomas), ampulla-duodenum, jejunoileum, anal canal, as well as for colorectal serrated polyposis and inflammatory bowel disease associated dysplasia (conventional and non-conventional). Knowledge gaps are also presented as they exist in rare cancers of the oesophagus (mixed type), appendix (mucinous neoplasms and mucinous adenomas), colorectum (three new subtypes) and anus, as well as for neuroendocrine tumours (grading, necrosis and two new gastric subtypes) and undifferentiated carcinomas (deficiencies of the SWI/SNF chromatin remodelling complex and mesenchymal differentiation). We identify and present research questions and persistent challenges for these entities and thus propose research frameworks that focus on specific priority areas. Progress in these core research topics for both neoplastic precursors and rare cancers will hopefully be reflected in future editions of the WCT, but many of these knowledge gaps will only be resolved with collective registries and collaborative research efforts. © 2026 The Author(s). The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Pathological neovascularization is the leading cause of childhood blindness in retinopathy of prematurity (ROP). Anti-vascular endothelial growth factor agents are commonly used to treat this condition, yet their variable efficacy and off-target effects demand alternative strategies. Here, we investigated the relationship between retinal dopamine (DA) dynamics and pathological angiogenesis in the oxygen-induced retinopathy (OIR) mouse model mimicking ROP pathogenesis. We determined the individual effects of apomorphine (APO), a non-selective DA receptor agonist, and selective agonists or antagonists of dopamine D1 receptor (Drd1) and dopamine D2 receptor (Drd2), on pathological neovascularization. Integrating single-cell RNA sequencing with Müller cell-specific Drd2 knockout OIR mice, we identified that Drd2-mediated signaling in Müller cells orchestrates hypoxia-inducible factor alpha and vascular endothelial growth factor A biosynthesis in Müller cells during the hypoxic–ischemic phase of OIR. Collectively, OIR-induced dopaminergic deficiency and impaired Drd2 activity in Müller cells synergistically exacerbate pathological angiogenesis. © 2026 The Pathological Society of Great Britain and Ireland.

Osteosarcoma (OS) is a primary bone malignancy, and its progression can be hindered by inducing programmed cell death (PCD). Protein disulfide-isomerase (PDI) regulates cancer cell death; however, its functional role in OS remains unclear. P4HB expression was assessed in tumor tissues and cells from patients with OS using RT-qPCR. The effects of P4HB on OS cell lines were evaluated. Western blotting was used to assess the impact of P4HB on various forms of PCD (apoptosis, ferroptosis, and pyroptosis). Bioinformatics analysis identified the upstream and downstream mechanisms of P4HB in OS progression. A xenograft tumorigenesis study was performed to elucidate the role and mechanism of P4HB in OS progression. Elevated P4HB expression was observed in OS tissue samples and cell lines. Downregulation of P4HB suppressed OS cell growth, migration, and invasiveness and induced PCD. Functional enrichment analysis and experimental validation revealed that PDI upregulated vascular endothelial growth factor A (VEGFA) vascular endothelial growth factor receptor 2 (VEGFR2) signaling. Methylation analysis showed that the m6A demethylase fat mass and obesity-associated protein (FTO) decreased P4HB m6A levels and enhanced VEGFA–VEGFR2 signaling in OS cells. Moreover, FTO overexpression enhanced the proliferative, migratory, and invasive capabilities of OS cells and decreased PCD. Finally, FTO knockdown inhibited tumor growth and lung metastasis of OS by decreasing the activity of the PDI/VEGFA–VEGFR2 signaling axis. Mechanistically, FTO-mediated m6A modification of P4HB regulates PCD in OS through activation of this axis. © 2026 The Pathological Society of Great Britain and Ireland.

Building on our previous research, which classified Kikuchi disease into three subtypes based on predominant symptoms and fever status – febrile type, febrile lymphadenopathy (FebLAP), and afebrile lymphadenopathy (aLAP) – we further investigated the underlying mechanisms contributing to their distinct clinical differences. Using NanoString nCounter technology, we analyzed the gene expression profiles of 35 Kikuchi disease lymph node specimens and compared them across the subtypes. Compared with the febrile type, aLAP exhibited higher AICDA expression, a trend observed in both germinal center positive and negative cases. The aLAP specimens also showed higher expression of B-cell markers; however, CD20 immunohistochemical staining did not reveal an increased number of B cells in aLAP. We therefore hypothesize that aLAP contains a higher proportion of atypical memory B cells, characterized by elevated AICDA and B-cell marker expression compared with other B-cell subsets. Immunohistochemical staining demonstrated that IRTA1+ atypical memory B cells were present in 64% (23/36) of aLAP cases, significantly higher than in FebLAP (0/8, 0%) and the febrile type (2/11, 18%) (p < 0.001). This finding confirms that aLAP is more likely to contain atypical memory B cells compared with the other subtypes. Pathway analysis revealed that the febrile type upregulates pathways associated with TLR2 and TLR4 signaling and neutrophil degranulation, while aLAP upregulates the TNFR2 non-canonical NF-κB pathway. RNAscope in situ hybridization demonstrated higher TLR4 expression in the febrile type compared with the aLAP type. These findings suggest that the triggering microbes for each subtype may differ, leading to distinct immune responses and clinical presentations. Overall, these results provide new insights into the immunopathogenesis of Kikuchi disease and highlight the potential role of atypical memory B cells in shaping its distinct clinical presentations. © 2026 The Pathological Society of Great Britain and Ireland.

Late-onset Fuchs endothelial corneal dystrophy (FECD) is characterized by distinct extracellular matrix deposits (guttae) within the basement membrane (Descemet's membrane) of the corneal endothelium. In a recent study published in The Journal of Pathology, Vaitinadapoulé et al (2026) describe the diversity of guttae patterns in FECD through analysis of 500 Descemet's membrane specimens removed during surgery, with genotyping performed in one-fifth of patients for the commonly associated TCF4 trinucleotide repeat expansion. The diversity and clustering of guttae phenotypes in the total cohort and in those with and without TCF4 association have implications for commonly used diagnostic grading criteria for FECD, the development of therapeutics, and our understanding of disease development. Investigating and embracing this diversity holds promise for advancing our understanding of FECD. © 2026 The Pathological Society of Great Britain and Ireland.

The extracellular matrix (ECM) plays a pivotal role in facilitating tumour development, invasiveness, metastasis, and immunoevasive processes through dynamic ECM remodelling processes. Testican-1 (SPOCK1), an excretory matricellular proteoglycan, is suggested to exert a role in the facilitation of ECM remodelling processes through interacting with matrix metalloproteases (MMPs) and even its less known forms. The structural mechanisms of interactions between testican-1 and MMPs were studied, and their roles in tumour-promotion pathway processes were also examined using a computational approach and immunofluorescence validated by colocalisation technique analysis. A computational analysis using docking, molecular dynamics (MD), and systems biology analysis was employed. HDock and GROMACS were chosen to analyse binding affinity and testican-1 stability with 28 different MMPs. H-bond, free energy, and root mean square fluctuation (RMSF) analyses were performed to confirm the interactions in the testican-1–MMP complexes. The systems biology toolkit implemented in this study consisted of STRING, BioGRID, and Cytoscape, which were employed for testican-1 interaction network and pathway analysis. Kaplan–Meier survival analysis using the GEPIA2 tool was utilised to correlate SPOCK1 gene expression and clinical survival measures for various malignancies. The docking analysis showed robust interactions between testican-1 and MMP23, MMP25, and MMP28. Additionally, testican-1–MMP complexes were confirmed to form stable interfaces based on comprehensive MD analysis, suggesting solid binding interfaces with the MMP-unique domain of testican-1. Our systems biology experiment indicated testican-1 as a central hub for interactions between immunoevasive and ECM remodelling processes. SPOCK expression was also shown to correlate with significant survival measures for different malignancies, revealing clinical implications in cancer. The testican-1–MMP computational analysis suggests testican-1 plays a pivotal role as a therapeutic target for a wide range of malignancies. SPOCK–MMP interactions could be targeted to interrupt tumour-promoting processes by arresting dynamic changes in the ECM, thereby improving patient survival. © 2026 The Author(s). The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.