Mumin Shao

Background and Aims: Metabolic dysfunction‐associated steatotic liver disease (MASLD) is a progressive liver disease that ranges from simple steatosis to inflammation, fibrosis and cirrhosis. To address the unmet need for new MASLD biomarkers, we aimed to identify candidate biomarkers using publicly available RNA sequencing (RNA‐seq) and proteomics data. Methods: An approach involving unsupervised gene clustering was performed using homogeneously processed and integrated RNA‐seq data of 625 liver specimens to screen for MASLD biomarkers, in combination with public proteomics data from healthy controls and MASLD patients. Additionally, we validated the results in the MASLD and healthy cohorts using enzyme‐linked immunosorbent assay (ELISA) of plasma and immunohistochemical staining (IHC) of liver samples. Results: We generated a database ( https://dreamapp.biomed.au.dk/NAFLD/ ) for exploring gene expression changes along MASLD progression to facilitate the identification of genes and pathways involved in the disease's progression. Through cross‐analysis of the gene and protein clusters, we identified 38 genes as potential biomarkers for MASLD severity. Up‐regulation of Quiescin sulfhydryl oxidase 1 ( QSOX1 ) and down‐regulation of Interleukin‐1 receptor accessory protein ( IL1RAP ) were associated with increasing MASLD severity in RNA‐seq and proteomics data. Particularly, the QSOX1/IL1RAP ratio in plasma demonstrated effectiveness in diagnosing MASLD, with an area under the receiver operating characteristic (AUROC) of up to 0.95 as quantified by proteomics profiling and an AUROC of 0.82 with ELISA. Conclusions: We discovered a significant association between the levels of QSOX1 and IL1RAP and MASLD severity. Furthermore, the QSOX1/IL1RAP ratio shows promise as a non‐invasive biomarker for diagnosing MASLD and assessing its severity.

The pathogenesis of gallbladder adenocarcinoma(GBC) remains inadequately elucidated. While its association with intestinal metaplasia (IM) has been acknowledged, there is a paucity of evidence connecting GBC to the most prevalent metaplastic type—pseudopyloric metaplasia (PPM). Given the morphological similarities between PPM and spasmolytic polypeptide-expressing metaplasia (SPEM), a recognized gastric precancerous condition, we propose that trefoil factor 2 (TFF2)-positive PPM may represent a cellular origin of GBC. Furthermore, we examine the role of the emerging therapeutic target claudin-18 (CLDN18) in this context. Through immunohistochemistry (IHC) analysis of 37 GBC, 30 biliary intraepithelial neoplasia (BilIN), 20 intracholecystic papillary neoplasm (ICPN), 26 IM, and 20 PPM samples, we observed an inverse correlation between CLDN18 expression and vascular invasion, whereas TFF2 expression was positively associated with tumor differentiation. CLDN18 overexpression(a staining intensity ≥ 2 + in ≥ 75% of tumour cells) was identified in 18.9% of GBC cases. This study provides the first evidence that CLDN18 is specifically activated at the precursor stage of gallbladder carcinogenesis, being strictly confined to lesions with an intestinal phenotype (IM, BilIN, ICPN) while remaining entirely negative in normal epithelium and PPM. This “all or none” expression pattern establishes CLDN18 as an ideal biomarker for identifying high risk gallbladder precursor lesions, particularly for recognizing PPM that has undergone malignant prone intestinal differentiation. Furthermore, the subset of GBCs with high CLDN18 expression identifies patients who may benefit from CLDN18 targeted therapies.

Patients presenting monoclonal gammopathy of renal significance (MGRS) and IgA vasculitis collectively have rarely been reported. This study reports one patient with monoclonal IgA and λ, and with IgA positive-mesangial proliferative glomerulonephritis. The patient manifested slight chronic nephritic syndrome, and his serums tested positive for M protein (monoclonal IgA and λ). As a result of bone wear, the plasma cell ratio of these patients was confirmed to be mildly increased in peripheral blood smears. Just like typical IgA nephropathy or IgA vasculitis patients, serum poorly galactosylated IgA1 antibodies were found in the patient compared to the controls. The patient was diagnosed with mild mesangial proliferative IgA vasculitis based on renal biopsy. Besides, immunofluorescence/immunohistochemistry confirmed immune deposits predominantly containing galactose-deficient IgA1 (GD-IgA1) and λ in the glomerular mesangium and the walls of the skin's blood vessels. The pathological findings support the hypothesis that monoclonal IgA, which originate from bone marrow plasma cells, rather than mucosally primed B cells, also may be galactose deficient. This may be a new pathological source of IgA-proliferative glomerulonephritis.

Aims Phyllodes tumours (PTs) are relatively common fibroepithelial tumours comprising epithelial and stromal component. Usually, PTs show a spindle cell morphology with a fibroblast phenotype, while some tumour cells exhibit epithelioid morphological features and sarcomatoid transformation. However, the molecular characteristics of this morphology subset remain unclear. This study aimed to summarise the clinicopathological, morphological and molecular characteristics of seven cases of PT with epithelioid features. Methods Morphological and clinicopathological characteristics were observed and retrieved. Immunohistochemistry, immunofluorescence and electron microscope were performed on seven cases of epithelioid PT to explore immunophenotypic and ultrastructural characteristics. Transcriptomic and proteomic analyses were conducted to compare differentially expressed genes and proteins between epithelioid PT and classical PT. Results Patients with epithelioid PT exhibit a high recurrence rate (42.8%). Morphologically, in addition to having epithelioid cytological features, neoplastic stromal cells exhibit moderate to marked atypia and often exhibit sarcomatoid transformation, similar to the characteristics of borderline PT. Transcriptomic and proteomic analyses demonstrated that epithelioid PTs are distinct from classical PTs in gene expression and protein abundance levels. Immunohistochemical analysis showed that among all differentially expressed proteins, epithelioid PT showed abnormal p16/retinoblastoma expression patterns, similar to those of malignant PT. Conclusions Epithelioid PT has unique morphological characteristics, biological behaviour and protein expression profile, which meets the diagnostic criteria of borderline PT and is prone to sarcomatoid transformation. It may be a special morphological subgroup of borderline PT and has partial characteristics of malignant PT, which should be taken seriously in pathological diagnosis and clinical management.

Background: Breast phyllodes tumours (PTs) are a unique type of fibroepithelial neoplasms with metastatic potential and recurrence tendency. However, the precise nature of heterogeneity in breast PTs remains poorly understood. This study aimed to elucidate the cell subpopulations composition and spatial structure and investigate diagnostic markers in the pathogenesis of PTs.Methods: We applied single‐cell RNA sequencing and spatial transcriptomes on tumours and adjacent normal tissues for integration analysis. Immunofluorescence experiments were conducted to verify the tissue distribution of cells. Tumour cells from patients with PTs were cultured to validate the function of genes. To validate the heterogeneity, the epithelial and stromal components of tumour tissues were separated using laser capture microdissection, and microproteomics data were obtained using data‐independent acquisition mass spectrometry. The diagnostic value of genes was assessed using immunohistochemistry staining.Results: Tumour stromal cells harboured seven subpopulations. Among them, a population of widely distributed cancer‐associated fibroblast‐like stroma cells exhibited strong communications with epithelial progenitors which underwent a mesenchymal transition. We identified two stromal subpopulations sharing epithelial progenitors and mesenchymal markers. They were inferred to further differentiate into transcriptionally active stromal subpopulations continuously expressing COL4A1/2. The binding of COL4A1/2 with ITGA1/B1 facilitated a growth pattern from the stroma towards the surrounding glands. Furthermore, we found consistent transcriptional changes between intratumoural heterogeneity and inter‐patient heterogeneity by performing microproteomics studies on 30 samples from 11 PTs. The immunohistochemical assessment of 97 independent cohorts identified that COL4A1/2 and CSRP1 could aid in accurate diagnosis and grading.Conclusions: Our study demonstrates that COL4A1/2 shapes the spatial structure of stromal cell differentiation and has important clinical implications for accurate diagnosis of breast PTs.