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Secretory carcinoma is a malignant salivary gland tumor, which typically presents as an indolent painless mass within the parotid gland. Involvement of the minor gland is reported but less common. Secretory carcinoma was often misclassified as other salivary gland mimics, particularly acinic cell carcinoma, prior to 2010. It was first recognized as a molecularly distinct salivary gland tumor harboring the same fusion gene as well as histologic and cytogenetic features seen in juvenile breast cancer. Secretory carcinoma is generally managed in the same way as other low-grade salivary gland neoplasms and has a favorable prognosis; however, high-grade transformation requiring aggressive therapeutic interventions have been documented. Recent studies of biologic agents targeting products of this fusion gene offer the promise of a novel therapeutic option for treatment of this malignancy. Due to the limited number of reported cases, the spectrum of clinical behavior, best practices for management, and long-term treatment outcomes for secretory carcinoma remain unclear. A long-standing secretory carcinoma involving minor salivary glands of the mucobuccal fold, which was detected years after it was first noted by the patient, is reported. This case brings to light the importance of a thorough clinical exam during dental visits and reviews diagnostic differentiation of this malignancy from other mimics and discusses decision making for its management. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the effect of interleukin-6 (IL-6) inhibitor (tocilizumab) on bacterial infection-associated bone resorption around implants during osseointegration in rabbits. Materials and Methods: At total of 24 male, 9-monthold New Zealand white rabbits were included, and their two mandibular anterior teeth were extracted. Three months after extraction, 24 one-piece Dentium implants (Ø 2.5 mm, intraosseous length of 12 mm) were inserted in the anterior mandible, and the rabbits were divided into four groups (n = 6 per group). Different treatment methods were used in each group: blank control group (BC); only silk ligation (negative control [NC]); silk ligation and injection with minocycline hydrochloride ointment (positive control [PC]); and silk ligation and injection with tocilizumab at 8 mg/kg via the auricle vein (experimental [EP]). Eight weeks later, the animals were sacrificed, and samples were collected and then analyzed using microcomputed tomography (microCT) scanning, immunohistochemical analysis, and histologic analysis. Results: From the microCT measurement, the ratio of the bone volume to the total volume (BV/TV) in the EP group was 67.00% ± 2.72%, which was higher than that in the other three groups (58.85% ± 2.43% in the BC group, 55.72% ± 2.48% in the PC group, and 36.52% ± 3.02% in the NC group). From immunohistochemical analysis, the expression of IL-6 was found to be higher in the NC group than in the BC, PC, and EP groups, but there was no statistical difference between these three groups. Furthermore, the RANKL (receptor activator of nuclear factor-κB ligand) expression was the lowest in the EP group, followed by the BC group, the PC group, and the NC group, which had the highest expression; there was no difference between the NC and PC groups. Upon histologic analysis, significant new bone was found on the implant surfaces in the EP group, sparse and less new bone could be seen in the BC and PC groups, and the most serious bone resorption occurred in the NC group. Conclusions: Tocilizumab, an inhibitor of IL-6, has a certain effect in preventing bone loss around implants caused by bacterial infection during the osseointegration period. [ABSTRACT FROM AUTHOR]

Ewing sarcoma (ES) is an uncommon mesenchymal neoplasm that typically develops as a bone mass, although up to 30% arise in extraskeletal sites. ES of the gastrointestinal (GI) and hepatobiliary tract is rare and may be misdiagnosed as other, more common neoplasms that occur in these sites. However, the correct classification of extraskeletal ES is important for timely clinical management and prognostication. We reviewed our experience of ES in the GI and hepatobiliary tract in order to further highlight the clinicopathologic features of these neoplasms and document the potential for misdiagnosis in this setting. The archives and consultation files of 6 academic institutions were retrospectively queried for cases of ES occurring in the GI and hepatobiliary tract. The histologic slides and ancillary studies were reviewed and clinical data were retrieved for each case through the electronic medical records, when available. Twenty-three patients with ES in the GI and/or hepatobiliary tract were identified from 2000 to 2022. Of these, 11 were women and 12 were men with a median age of 38 years (range, 2 to 64). Tumor locations included the pancreas (n=5), liver (n=2), stomach (n=3), colorectum (n=3), and small intestine (n=5), as well as tumors involving multiple organs, pelvis and retroperitoneum (n=5). Tumor size varied between 2 cm and 18 cm. Twenty were primary and 3 were metastases. Of the 23 cases, only 17% were initially diagnosed as ES. The most common misdiagnoses involved various forms of neuroendocrine neoplasia due to expression of synaptophysin and other neuroendocrine markers (22%). A wide variety of diagnoses including GI stromal tumor was considered due to aberrant CD117 expression (4%). The diagnosis of ES was ultimately confirmed by detection of the EWSR1 rearrangement in 22 cases. The remaining case was diagnosed using traditional immunohistochemistry. Follow-up information was available in 20 cases, with follow-up time varying between 2 and 256 months. Six patients with follow-up died of disease between 6 and 60 months following initial presentation. Our data indicate ES in the GI and hepatobiliary tract is commonly misdiagnosed leading to a delay in therapy. In light of the attendant therapeutic and prognostic implications, ES should be considered in the differential diagnosis of any GI or hepatobiliary tumor with epithelioid and/or small round cell morphology.

Mannheimia haemolytica-associated abomasitis has been clinically described as a cause of sudden death in lambs, but it is poorly characterized. We describe the pathological features of a severe fibrinonecrotizing abomasitis in 3 lambs that died suddenly. All 3 abomasums had a thickened submucosa due to edema and necrotic areas delimited by bands of degenerate neutrophils with slender nuclei (oat cells) and angiocentric distributions. The overlying mucosa was congested. Myriads of gram-negative coccobacilli were observed within the oat cell bands. M. haemolytica was isolated from the abomasum in all 3 animals and was serotyped as A2 in one of them. Pericarditis and pleuritis were observed in 2 of the lambs. Clostridium spp. were isolated in 1 lamb and detected by immunohistochemistry in the 3 animals, suggesting clostridial co-infection. M. haemolytica should be considered among the differential diagnoses of necrotizing abomasitis in lambs.

Immunohistochemistry (IHC) is used to guide treatment decisions in multiple cancer types. For treatment with checkpoint inhibitors, programmed death ligand 1 (PD-L1) IHC is used as a companion diagnostic. However, the scoring of PD-L1 is complicated by its expression in cancer and immune cells. Separation of cancer and noncancer regions is needed to calculate tumor proportion scores (TPS) of PD-L1, which is based on the percentage of PD-L1-positive cancer cells. Evaluation of PD-L1 expression requires highly experienced pathologists and is often challenging and time-consuming. Here, we used a multi-institutional cohort of 77 lung cancer cases stained centrally with the PD-L1 22C3 clone. We developed a 4-step pipeline for measuring TPS that includes the coregistration of hematoxylin and eosin, PD-L1, and negative control (NC) digital slides for exclusion of necrosis, segmentation of cancer regions, and quantification of PD-L1+ cells. As cancer segmentation is a challenging step for TPS generation, we trained DeepLab V3 in the Visiopharm software package to outline cancer regions in PD-L1 and NC images and evaluated the model performance by mean intersection over union (mIoU) against manual outlines. Only 14 cases were required to accomplish a mIoU of 0.82 for cancer segmentation in hematoxylin-stained NC cases. For PD-L1-stained slides, a model trained on PD-L1 tiles augmented by registered NC tiles achieved a mIoU of 0.79. In segmented cancer regions from whole slide images, the digital TPS achieved an accuracy of 75% against the manual TPS scores from the pathology report. Major reasons for algorithmic inaccuracies include the inclusion of immune cells in cancer outlines and poor nuclear segmentation of cancer cells. Our transparent and stepwise approach and performance metrics can be applied to any IHC assay to provide pathologists with important insights on when to apply and how to evaluate commercial automated IHC scoring systems.

BackgroundS100A8 is a melanoma biomarker expressed in the melanoma-associated epidermal keratinocytes, but its diagnostic utility has not been compared with other biomarkers, including PRAME.ObjectivesTo compare the utility of S100A8 and PRAME immunohistochemistry (IHC) in the differential diagnosis of melanoma and naevi in a case-control study.MethodsA previously described cohort of 209 melanomas (case samples) and naevi (control samples) dual-immunostained for S100A8 and PRAME were included. For S100A8, previously reported scores indicating the proportion of tumour-associated epidermis stained (0 = indeterminate; 1 = 0-4%; 2 = 5-25%; 3 = 26-50%; 4 = 51-75%; 5 = > 75%) were utilized. PRAME IHC was reviewed by at least two reviewers and a consensus score assigned, with score indicating the proportion of tumour stained (0 = indeterminate; 1 = 0%; 2 = 1-50%; 3 = > 50%). A positive test was defined as > 50% staining.ResultsThe area under the receiver operating characteristic curves for S100A8 (0.833) and PRAME (0.874) were not significantly different from each other (P = 0.22). The diagnostic sensitivity and specificity were 42.4% [95% confidence interval (CI) 32.6-52.8%] and 98.2% (95% CI 93.6-99.8%) for S100A8, and 79.8% (95% CI 70.5-87.2%) and 87.3% (95% CI 79.6-92.9%) for PRAME, respectively. A combined test requiring both S100A8 and PRAME IHC positivity had a sensitivity of 39.4% (95% CI 29.7-49.7%) and specificity of 99.1% (95% CI 95.0-100.0%).ConclusionsS100A8 and PRAME have utility in the diagnostic workup of melanoma, with S100A8 being more specific and PRAME being more sensitive when using this threshold. Our findings suggest that these two immunohistochemical markers may favourably complement one another to improve the detection of melanoma.

Salivary glands have essential roles in maintaining oral health, mastication, taste and speech, by secreting saliva. Salivary glands are composed of several types of cells, and each cell type is predicted to be involved in the carcinogenesis of different types of cancers including adenoid cystic carcinoma (ACC), acinic cell carcinoma (AciCC), salivary duct carcinoma (SDC), myoepithelial carcinoma (MECA) and other histology. In our study, we performed single nucleus RNA-seq on three human salivary gland samples to clarify the gene expression profile of each complex cellular component of the salivary glands and related these expression patterns to expression found in salivary gland cancers (SGC) to infer cell of origin. By single nucleus RNA-seq, salivary gland cells were stratified into four clusters: acinar cells, ductal cells 1, ductal cells 2 and myoepithelial cells/stromal cells. The localization of each cell group was verified by IHC of each cluster marker gene, and one group of ductal cells was found to represent intercalated ductal cells labeled with HES1. Furthermore, in comparison with SGC RNA-seq data, acinar cell markers were upregulated in AciCC, but downregulated in ACC and ductal cell markers were upregulated in SDC but downregulated in MECA, suggesting that markers of origin are highly expressed in some SGC. Cell type expressions in specific SGC histology are similar to those found in normal salivary gland populations, indicating a potential etiologic relationship.

Purpose: To investigate bone regeneration among three different bone graft materials in a rat calvarum model. Materials and Methods: A total of 24 rats had two 5-mm defects placed per calvarial. Rats were divided into four groups: bovine xenograft (XG), demineralized bone matrix (DBM), mineralized bone graft (MBG), and collagen membrane control (CC). Within each group, samples were collected at two time points: 4 weeks (T4) and 8 weeks (T8). Bone regeneration was assessed by microcomputed tomography (micro-CT) imaging and was analyzed using MATLAB software. Additionally, the fixed samples were subsequently demineralized for immunohistochemistry and histomorphometry. Slides were mounted and stained with hematoxylin and eosin (H&E) stain as well as bone morphogenetic protein 2 (BMP-2) and runt-related transcription factor 2 (RUNX2) markers. The numbers of positive cells/area were calculated for each group and analyzed. Results: At 4 weeks, DBM showed low mineral density (7.7%) compared to the control (25.2%), but increased dramatically at 8 weeks (DBM, T8 = 27.6%; CC, T8 = 27.2%). Xenograft material showed an increase in mineral desnity between T4 and T8 (XG, T4 = 25.0%; XG, T8 = 32.3%). MBG remained consistent over the 8-week trial period (MBG, T4 = 30.4%; MBG, T8 = 30.4%). BMP-2 expression was present in cells adherent to all graft materials. RUNX2 expression was also observed in cells adherent to all graft materials, indicating that during the 4- to 8-week healing period, all materials supported osteogenesis. Conclusions: Compared to other materials, the DBM had high osteoinductive properties during the 4- to 8-week time period based on increased mineral content. All materials were associated with immunohistologic evidence of osteogenesis in the rat calvarial defect model. [ABSTRACT FROM AUTHOR]

Purpose: To analyze the process of early oral osseointegration of titanium (Ti) implants in diabetic 129/Sv mice through microCT and histologic and immunohistochemical analysis. Materials and Methods: A group of 30 male 129/Sv mice was equally subdivided into two groups: (1) nondiabetic (ND), in which mice did not undergo systemic alterations and received a standard diet, and (2) diabetic (D), in which mice were provided a high-fat diet from the age of 6 weeks until the conclusion of the study and received two intraperitoneal (IP) injections of streptozotocin (STZ) at a concentration of 100 mg/Kg each. Each mouse underwent extraction of a maxillary first molar, and customized Ti screws (0.50 mm diameter, 1.5 mm length) were placed in the residual alveolar sockets of the palatal roots. At 7 and 21 days after implant placement, the animals were euthanized for maxilla and pancreas collection. Maxillae containing Ti implants were analyzed with microCT, histology, and immunohistochemistry for cells that were positive for F4/80, CD146, runt-related transcription factor 2 (Runx2), and proliferating cell nuclear antigen (PCNA). Pancreata were histologically analyzed. Quantitative data were statistically analyzed with a significance level at 5% (P < .05). Results: ND mice presented successful healing and osseointegration, with a significantly higher fraction of bone volume compared to D mice, both at the alveolar sockets (53.39 ± 5.93 and 46.08 ± 3.18, respectively) and at the implant sites (68.88 ± 7.07 and 44.40 ± 6.98, respectively) 21 days after implant placement. Histologic evaluation revealed that the ND mice showed a significant decrease in inflammatory infiltrate and a significant increase in newly formed bone matrix at 21 days, whereas peri-implant sites in the D mice were predominantly encapsulated by fibrous tissue and chronic inflammatory infiltrate. Immunohistochemical characterization revealed higher Runx2 osteoblast differentiation and higher cell proliferation activity in the ND mice at 7 days, while higher amounts of macrophages were present in D mice at 7 and 21 days. Interestingly, no differences were found in CD146-positive cells when comparing ND and D mice. Conclusions: This study evaluated the effects of immediate dental implant placement in 129/Sv diabetic mice by using specific healing markers to identify changes in cellular events involved in early oral osseointegration. This approach may serve as tool to evaluate new materials and surface coatings to improve osseointegration in diabetic patients. [ABSTRACT FROM AUTHOR]

Novel brain clearing methods revolutionize imaging by increasing visualization throughout the brain at high resolution. However, combining the standard tool of immunostaining targets of interest with clearing methods has lagged behind. We integrate whole-mount immunostaining with PEGASOS tissue clearing, referred to as iPEGASOS (immunostaining-compatible PEGASOS), to address the challenge of signal quenching during clearing processes. iPEGASOS effectively enhances molecular-genetically targeted fluorescent signals that are otherwise compromised during conventional clearing procedures. Additionally, we demonstrate the utility of iPEGASOS for visualizing neurochemical markers or viral labels to augment visualization that transgenic mouse lines cannot provide. Our study encompasses three distinct applications, each showcasing the versatility and efficacy of this approach. We employ whole-mount immunostaining to enhance molecular signals in transgenic reporter mouse lines to visualize the whole-brain spatial distribution of specific cellular populations. We also significantly improve the visualization of neural circuit connections by enhancing signals from viral tracers injected into the brain. Last, we show immunostaining without genetic markers to selectively label beta-amyloid deposits in a mouse model of Alzheimers disease, facilitating the comprehensive whole-brain study of pathological features.

Endothelial cells of mammalian blood vessels have multiple levels of heterogeneity along the vascular tree and among different organs. Further heterogeneity results from blood flow turbulence and variations in shear stress. In the aorta, vascular endothelial protein tyrosine phosphatase (VE-PTP), which dephosphorylates tyrosine kinase receptor Tie2 in the plasma membrane, undergoes downstream polarization and endocytosis in endothelial cells exposed to laminar flow and high shear stress. VE-PTP sequestration promotes Tie2 phosphorylation at tyrosine992 and endothelial barrier tightening. The present study characterized the heterogeneity of VE-PTP polarization, Tie2-pY992 and total Tie2, and claudin-5 in anatomically defined regions of endothelial cells in the mouse descending thoracic aorta, where laminar flow is variable and IgG extravasation is patchy. We discovered that VE-PTP and Tie2-pY992 had mosaic patterns, unlike the uniform distribution of total Tie2. Claudin-5 at tight junctions also had a mosaic pattern, whereas VE-cadherin at adherens junctions bordered all endothelial cells. Importantly, the amounts of Tie2-pY992 and claudin-5 in aortic endothelial cells correlated with downstream polarization of VE-PTP. VE-PTP and Tie2-pY992 also had mosaic patterns in the vena cava, but claudin-5 was nearly absent and extravasated IgG was ubiquitous. Correlation of Tie2-pY992 and claudin-5 with VE-PTP polarization supports their collective interaction in the regulation of endothelial barrier function in the aorta, yet differences between the aorta and vena cava indicate additional flow-related determinants of permeability. Together, the results highlight new levels of endothelial cell functional mosaicism in the aorta and vena cava, where blood flow dynamics are well known to be heterogeneous.

Context.--Human epidermal growth factor (HER2/neu) gene amplification, a poor prognostic factor in invasive breast cancer, has shown substantial utility as a predictive marker, with significantly improved survival following anti-HER2 therapies like trastuzumab. Dual-color dual in situ hybridization (D-DISH), a recently introduced fully automated assay for HER2/neu evaluation on light microscopy, has several advantages over fluorescence in situ hybridization (FISH). Objective.--To standardize and validate the D-DISH assay using FISH as the gold standard and assess interobserver reproducibility in interpreting the D-DISH assay. Design.--D-DISH was performed using the latest HER2 Dual ISH DNA Probe Cocktail assay (Ventana Medical Systems Inc, Tucson, Arizona) in 148 cases of invasive breast cancer. The same block was used for performing immunohistochemistry by Ventana PATHWAY anti-HER2/neu (4B5) antibody and FISH assay by ZytoLight SPEC ERBB2/CEN17 Dual Color Probe. D-DISH was separately interpreted by 4 pathologists blinded to FISH results. Results.--Concordance of 98.65% and a Cohen [kappa] value of 0.97 were observed between FISH and D-DISH. Intraclass correlation coefficient (0.93-0.97) and [kappa] values (0.98-1.0) for interobserver reproducibility showed almost perfect agreement by D-DISH. Interobserver reproducibility was also evaluated for genomic heterogeneity, HER2 group categorization, and polysomy (k values 0.42-0.74, 0.89-0.93, and 0.98-1.0, respectively). Conclusions.--We successfully validated the latest version of D-DISH assay as a substitute for FISH in predicting HER2 gene status with significant interobserver reproducibility, concluding that this D-DISH assay may be introduced in routine diagnostic services as a reflex test to ascertain HER2 gene status. doi: 10.5858/arpa.2022-0543-0A, The human epidermal growth factor (HER2/neu) gene, located on the long arm of human chromosome 17 (17q12), is associated with aggressive tumor behavior and has emerged as an independent prognostic [...]

Objective: To histologically evaluate the effects of a novel human recombinant amelogenin (rAmelX) on periodontal wound healing/regeneration in intrabony defects. Method and mater-ials: Intrabony defects were surgically created in the mandible of three minipigs. Twelve defects were randomly treated with either rAmelX and carrier (test group) or with the carrier only (control group). At 3 months following reconstructive surgery, the animals were euthanized, and the tissues histologically processed. Thereafter, descriptive histology, histometry, and statistical analyses were performed. Results: Postoperative clinical healing was uneventful. At the defect level, no adverse reactions (eg, suppuration, abscess formation, unusual inflammatory reaction) were observed with a good biocompatibility of the tested products. The test group yielded higher values for new cementum formation (4.81 ± 1.17 mm) compared to the control group (4.39 ± 1.71 mm) without reaching statistical significance (P= .937). Moreover, regrowth of new bone was greater in the test compared to the control group (3.51 mm and 2.97 mm, respectively, P = .309). Conclusions: The present results provided for the first-time histologic evidence for periodontal regeneration following the use of rAmelX in intrabony defects, thus pointing to the potential of this novel recombinant amelogenin as a possible alternative to regenerative materials from animal origins. [ABSTRACT FROM AUTHOR]

Aims Methods and results Conclusions Recently, SOX17 has emerged as a promising biomarker for non‐mucinous Müllerian (ovarian and endometrial) carcinomas, demonstrating increased specificity in comparison to PAX8 while maintaining similar sensitivity. However, expression of SOX17 in mesonephric‐like adenocarcinoma (MLA), a carcinoma of the female genital tract with uncertain, but probably Müllerian histogenesis, remains unexplored. This study aims to address this gap.SOX17 immunohistochemistry was performed on whole tissue sections from 68 MLAs originating from the endometrium or ovary and seven cervical mesonephric carcinomas, as well as six mesonephric remnants/hyperplasias. Using a four‐tiered scoring system based on distribution and intensity of staining, 68% of MLA displayed a negative/low (< 10%) SOX17 expression pattern, which contrasts with the high expression observed in most Müllerian carcinomas. However, 22% of MLA demonstrated high SOX17 expression, similar to other endometrial and ovarian carcinomas. Similarly, five of seven (72%) mesonephric carcinomas of the cervix were SOX17‐negative, but two cases (28%) were positive. All mesonephric remnants/hyperplasias were SOX17 negative.The majority of MLA are negative or exhibit low SOX17 expression, in contrast to the diffuse and strong expression commonly seen in other types of Müllerian carcinoma. However, a subset of MLAs demonstrate high SOX17 expression. Therefore, absence of SOX17 staining is supportive for MLA when the differential includes another non‐mucinous Müllerian carcinoma. SOX17 may also be useful for differentiating mesonephric remnants/hyperplasias from Müllerian malignancies and benign Müllerian glandular lesions. [ABSTRACT FROM AUTHOR]

Thyroid tissue in teleosts is located mainly in the pharyngeal region, usually reaching other adjacent anatomical locations. Herein, a nodular lesion located in the left operculum of a Senegal seabream (Diplodus bellottii) was surgically excised and sent for microscopical evaluation. Microscopically, the lesion presented irregular borders and consisted in columnar epithelial cells arranged in a tubulopapillary pattern, surrounding a central lumen filled with acellular, acidophilic and homogeneous, material (‘colloid’). To determine the lesion's histogenesis, immunohistochemistry was performed employing antibodies for AE1/AE3, CK7, thyroglobulin and vimentin. The neoplastic cells presented low mitotic index and positive immunolabelling for CK7 and thyroglobulin. Therefore, a diagnosis of ectopic thyroid adenoma was made. Herein, the successful employment of antibodies classically used in mammals for accurate diagnosis of thyroid disorders is described. Proliferation of thyroid tissue in fish may reflect environmental and physiological imbalances, making the study and correct diagnosis of these tumours in this species important. [ABSTRACT FROM AUTHOR]

Organoids are in vitro tissue models derived from human or animal primary tissues or stem cells that allow for studying three-dimensional (3D) tissue biology, toxicity testing, biomarker evaluation, and assessment of compound efficacy, supplementing or potentially minimizing use of animal models. Organoids are typically cultured in a 3D format within an extracellular matrix and, at the end of an experiment, can be further processed for various cellular or molecular readouts. Analysis often relies on whole mount immunolabeling for markers of interest, which consumes the entire sample/well, thereby limiting sample availability for downstream assays. In addition, 3D cultures become more friable after fixation and are susceptible to sample loss during washing steps. In contrast, by fixing and processing organoids to a paraffin block, dozens or hundreds of unstained slides can be generated, enabling robust characterization via multiple assays, including histologic evaluation and (immuno)histochemical stains, thus maximizing the yield of these time- and labor-intensive cultures. Here we describe three methods to process 3D Matrigel cultures into paraffin blocks using Histogel as an embedding agent. The three techniques all yield high-quality sections but vary in complexity of implementation at different steps, and their application for different use cases is discussed. [ABSTRACT FROM AUTHOR]

BACKGROUND: The temporal and spatial expression of fibroblast growth factor receptors 1 and 2 remains a controversial issue during kidney development, so the relationship between them and kidney development remains unclear. OBJECTIVE: To observe the dynamic expression of fibroblast growth factor receptors 1 and 2 during kidney development of mice, and to investigate the relationship between them and kidney development. METHODS: The kidneys of fetal mice [embryotic days (E) 12, 14, 16, and 18] and neonatal mice [neonatal days (N) 1, 3, 7, 14, 24, and 40] were selected to examine the temporal and spatial expression of fibroblast growth factor receptors 1 and 2 by immunohistochemistry method in kidney tissues, and quantitative analysis was performed using western blot assay. RESULTS AND CONCLUSION: (1) Immunohistochemistry showed that fibroblast growth factor receptor 1 was mainly localized in metanephric tissue surrounding the tip of the ureteral bud at E12. Subsequently, fibroblast growth factor receptor 1 was expressed in immature renal corpuscles at various stages, some distal convoluted tubules and capillary loops. The positive site was mainly concentrated in the generative region. Fibroblast growth factor receptor 2 was initially expressed in both ureteral buds and metanephric tissue. Fibroblast growth factor receptor 2 was localized in immature renal corpuscles, distal tubules, collecting ducts and thin segments of medullary loops with kidney development. However, the expression of renal corpuscles was weak. (2) Stereology and western blot assay showed that the expression of fibroblast growth factor receptor 1 was high before birth and gradually decreased after birth, while the expression was very low after N7 day. The expression level of fibroblast growth factor receptor 2 increased gradually with the kidney development and tended to be stable after N7 day. (3) The results exhibit that fibroblast growth factor receptors 1 and 2 are expressed spatially and temporally during kidney development. It is speculated that fibroblast growth factor receptors 1 and 2 may influence nephron development and maturation, and fibroblast growth factor receptor 2 is critical during the formation of ureteral buds and morphology. [ABSTRACT FROM AUTHOR]

Objectives: We explored Trichorhinophalangeal syndrome type 1 (TRPS1) expression in special types of breast carcinoma, and analyzed the correlation between TRPS1 and androgen receptor (AR) expression in triple-negative breast cancer (TNBC). Methods: TRPS1 expression was analyzed in 801 patients with special types of breast carcinoma. A total of 969 TNBC were used to analyze the correlation between the expression of TRPS1 and AR. TRPS1 expression was evaluated in 1975 cases of breast cancer with different molecular types. Results: A total of 801 special types of breast cancers were stained with TRPS1.TRPS1 was positive in 100% (63/63) of mucinous carcinoma, 100% (7/7) adenoid cystic carcinomas (4 classic adenoid cystic carcinomas and 3 solid-basaloid adenoid cystic carcinomas), 100% (4/4) tubular carcinomas, 100% (2/2) secretory carcinomas, and 99.59% (243/244) invasive lobular carcinomas, 99.26% (267/269) invasive micropapillary carcinomas, 97.44% (38/39) ER-positive neuroendocrine tumors, 94.44% (34/36) metaplastic breast carcinomas (MBCs), 63.73% (65/102) apocrine carcinomas. TRPS1 was negative in all triple-negative neuroendocrine carcinomas (0/7).TRPS1 was positive in 92.86% (26/28) of metastatic special types of breast cancer. TRPS1 and AR expression were analyzed in 969 cases of TNBC. 90.40% were positive for TRPS1, and 42.41% were positive for AR. A significant inverse correlation between TRPS1 and AR expression was shown in TNBC (p <.001). TRPS1 showed a higher positive rate (93.13%) in TNBC compared to GATA binding protein 3 (GATA3), gross cystic disease fluid protein 15 (GCDFP-15) and forkhead box transcription Factor C 1 (FOXC1). Conclusions: In conclusion, our study demonstrated that TRPS1 is a highly sensitive marker for most special types of breast carcinoma. TRPS1 was positive in 63.73% of apocrine carcinomas. TRPS1 and AR expression was inversely correlated in TNBC. [ABSTRACT FROM AUTHOR]

Aims Methods Results Conclusion Mesonephric‐like adenocarcinoma (MLA) of the endometrium or ovary is a rare but distinct endometrial carcinoma which has a combination of characteristic morphological, immunohistochemical (IHC) and molecular features. SOX17 has been recently identified as a highly sensitive and specific marker for endometrial and ovarian carcinomas. In this study, we aimed to investigate SOX17 expression in MLA together with other IHCs to differentiate MLAs from other endometrial carcinomas.Seventeen previously diagnosed endometrial/ovarian MLAs were collected, and multiple IHCs were performed. Additionally, we performed SOX17, PAX8 and ER on tissue microarrays (TMAs) composed of 652 endometrial carcinomas from 2012 to 2015 when MLA diagnostic criteria were not established.All 17 MLAs showed diffuse strong positive PAX8, negative ER and variable TTF1/GATA3 staining. Notably, all MLAs showed negative (n = 10) or focal weak/moderate (n = 7) staining for SOX17, which is more diffuse and stronger than PAX8 in other endometrial carcinoma subtypes. This finding prompted us to screen TMAs with 652 endometrial carcinomas diagnosed before MLA by an approach of combined SOX17 and PAX8 IHCs, and 14 cases with positive PAX8 but negative/focal weak SOX17 were identified. We further studied the 14 cases by examining morphology and performing additional IHCs (TTF1, GATA3, ER and CD10) and would classify seven (50%) of them as MLAs based on morphological features and positive CD10, TTF1 and/or GATA3 staining.Our results suggest that a combination of SOX17 and PAX8 IHCs would aid in diagnosing MLA if the results show strong positive PAX8, but negative SOX17. [ABSTRACT FROM AUTHOR]

Background: Distant metastases from lung cancer are commonly found in the brain, bone, and liver. Metastases to the breast from non-mammary malignancies are extremely rare, and their clinical presentations remain unclear. Case presentation: We herein report a case of bilateral breast metastases from anaplastic lymphoma kinase-positive advanced lung cancer in a 51-year-old Japanese male patient. During the course of systemic treatment for advanced lung cancer, computed tomography revealed bilateral breast enlargement without contrast enhancement, a finding consistent with gynecomastia. While other metastatic lesions responded to chemotherapy, both breast masses grew vertically like nodules. The breast masses were immunohistochemically diagnosed as metastases from lung cancer and were removed surgically. Simultaneous bilateral breast metastases from malignancies of other organs, like ones in this case, have rarely been described. Conclusions: It is important to keep in mind that breast metastases from nonmammary malignancies are a possible explanation for unusual breast findings in a patient with a history of malignancies. [ABSTRACT FROM AUTHOR]

Aim Methodology Results Conclusions To evaluate M1 and M2 macrophage polarization in radicular cysts and periapical granulomas through an immunohistochemical analysis and the correlation between macrophage polarization and histopathological diagnosis, clinical characteristics and lesion volume using cone‐beam computed tomography.Periapical biopsies diagnosed as radicular cysts (n = 52) and periapical granulomas (n = 51) were analysed by immunohistochemical method. Teeth with periapical lesion with no history of root canal treatment (primary lesion) and lesions persistent to root canal treatment (persistent lesions) were included. Pathological diagnosis, patients' age, gender and clinical characteristics were obtained from treatment records. A cone‐beam computed tomographic periapical volume index (CBCTPAVI) score was assigned to each periapical lesion based on the volume of the lesion. Immuno‐expressions of CD68 and CD163 were quantified. The CD68/CD163 ratio was adopted to represent M1 or M2 macrophage polarization. Mann–Whitney U test was used to determine the different CD68/CD163 ratio between groups of radicular cyst and periapical granuloma. Spearman's correlation test was performed to assess the correlation between the CD68/CD163 ratio and lesion volume and CBCTPAVI score.Radicular cysts and periapical granulomas had CD68/CD163 median of 2.05 (IQR = 1.33) and 1.26 (IQR = 0.81), respectively. A significantly higher CD68/CD163 ratio was observed in radicular cysts (p < .001). In contrast, periapical granulomas had significantly lower median of CD68/CD163 ratio. Larger lesions had a higher median of CD68/CD163 ratio, while smaller lesions had lower median of CD68/CD163 ratio (p = .007, rs = .262). CD68/CD163 ratio was significantly correlated with the CBCTPAVI score in the overall periapical lesions (p = .002, rs = .306). The higher CD68/CD163 ratio in larger lesions indicated a higher degree of M1 polarization compared to smaller lesions. Regarding the pathological diagnosis, there was a significant positive correlation between CBCTPAVI score and CD68/CD163 ratio in periapical granulomas (p < .001, rs = .453), whereas the negative correlation was observed for radicular cysts (p < .001, rs = −.471).Periapical granulomas are characterized by a M2‐dominant macrophage polarization, while radicular cysts have significantly higher M1 macrophages. The higher degree of M1 macrophage polarization was significantly correlated with larger volume and higher CBCTPAVI scores of overall periapical lesion and periapical granuloma. [ABSTRACT FROM AUTHOR]

Background: Pancreatic hamartoma, a rare benign non-neoplastic condition, presents challenges in differentiating from other pancreatic diseases due to its atypical imaging and unreliable biopsy results. In this study, we present a case of pancreatic hamartoma and conduct a comprehensive review of relevant literature to outline its characteristic features, aiming to underscore its clinical relevance and implications. Case presentation: A 63-year-old man presented with a pancreatic mass, discovered during evaluation of abdominal pain and distension. Laboratory tests were largely unremarkable. Ultrasound revealed a hypoechoic mass in the head of the pancreas. Subsequent computed tomography and magnetic resonance imaging demonstrated an inhomogeneous mass with a clear boundary in the uncinate process of the pancreas. Furthermore, a distinct delayed enhancement pattern was noted on imaging. Histopathological examination confirmed the diagnosis of pancreatic hamartoma. Conclusions: Preoperative diagnosis of pancreatic hamartoma remains challenging. Imaging modalities can play a crucial role in facilitating accurate diagnosis and potentially avoiding unnecessary surgical intervention in patients with this condition. [ABSTRACT FROM AUTHOR]

Background: Sonic Hedgehog (Shh), extensively researched for its role in early neurogenesis and brain development, has recently been recognized for its neuroprotective potential following neuronal injuries. This study examines the immediate impact of early administered Shh on the local inflammatory response post-acute spinal cord injury in rats. Methods: Thirty-four female Wistar rats underwent either sham surgery (laminectomy; n = 10) or clip compression/contusion spinal cord injury (SCI) at the T9 level. This was followed by implantation of an osmotic pump and a subdural catheter for continuous intrathecal delivery of Shh (n = 12) or placebo (NaCl; n = 12). Locomotor function was assessed at 3- and 7-days post-injury (dpi) using the Basso, Beattie, and Bresnahan (BBB) score and the Gridwalk test. Animals were euthanized after 3 or 7 days for immunohistochemical analysis of the local inflammatory reaction and immune cell migration. Results: Shh-treated rats demonstrated significant hindlimb movement and coordination improvements at 7 days post-injury, compared to controls. This enhancement was accompanied by a significant reduction in both immune cell presence and blood plasma products within spinal cord lesions, suggesting Shh's dual role in modulating immune cell migration and maintaining the integrity of the blood-spinal cord barrier. Separately, these Shh-treated rats also showed an increase in M(IL-4) polarization of macrophages, further underlining the potential therapeutic impact of Shh in post-injury recovery. Notably, these effects were not evident at three days post-injury. Conclusion: Shh application at 7 days post-injury showed immunomodulatory effects, possibly via enhanced blood-spinal cord barrier integrity, reduced immune cell migration, and increased anti-inflammatory immune cell differentiation. These mechanisms collectively contribute to enhanced locomotor recovery. [ABSTRACT FROM AUTHOR]

Background: In 2022, our team launched the pioneering national proficiency testing (PT) scheme for the pathological diagnosis of breast cancer, rapidly establishing its credibility throughout China. Aiming to continuously monitor and improve the proficiency of Chinese pathologists in breast pathology, the second round of the PT scheme was initiated in 2023, which will expand the number of participating institutions, and will conduct a nationwide investigation into the interpretation of HER2 0, 1+, and 2+/FISH- categories in China. Methods: The methodology employed in the current round of PT scheme closely mirrors that of the preceding cycle in 2022, which is designed and implemented according to the "Conformity assessment—General requirements for proficiency testing"(GB/T27043—2012/ISO/IEC 17043:2010). More importantly, we utilized a statistics-based method to generate assigned values to enhance their robustness and credibility. Results: The final PT results, published on the website of the National Quality Control Center for Cancer (http://117.133.40.88:3927), showed that all participants passed the testing. However, a few institutions demonstrated systemic biases in scoring HER2 0, 1+, and 2+/FISH- with accuracy levels below 59%, considered unsatisfactory. Especially, the concordance rate for HER2 0 cases was only 78.1%, indicating challenges in distinguishing HER2 0 from low HER2 expression. Meanwhile, areas for histologic type and grade interpretation improvement were also noted. Conclusions: Our PT scheme demonstrated high proficiency in diagnosing breast cancer in China. But it also identified systemic biases in scoring HER2 0, 1+, and 2+/FISH- at some institutions. More importantly, our study highlighted challenges in the evaluation at the extreme lower end of the HER2 staining spectrum, a crucial area for further research. Meanwhile, it also revealed the need for improvements in interpreting histologic types and grades. These findings strengthened the importance of robust quality assurance mechanisms, like the nationwide PT scheme conducted in this study, to maintain high diagnostic standards and identify areas requiring further training and enhancement. [ABSTRACT FROM AUTHOR]

Introduction: Brain metastases are the most common malignant lesions in the central nervous system. Brain metastases from pancreatic cancer are very rare, with poor prognosis. The present paper aims to describe a rare pathology and the work carried out for the patient's care. Case report: 49-year-old man with personality changes, depression, and apathy. Five days before admission, he presented dysarthria, added left hemiparesis, and disorientation that progressed to sudden neurological deterioration that required advanced airway management. A computed tomography study was seen with cerebral cystic lesions. A decompressive craniectomy and drainage of the larger lesion was performed, with subsequent resection. The study protocol with immunohistochemistry reports CK 19, compatible with pancreatic adenocarcinoma. Conclusions: A rare case of multiple brain metastases and suspected lung metastasis, both secondary to primary pancreatic adenocarcinoma was presented. The patient began with symptoms associated with brain lesions. The incidence of brain metastases with a primary pancreatic tumor is very low, and this is an exceptional case when presenting with neurological symptoms. Surgical resection of the brain lesion had a limited role in the clinical improvement of the patient since the progression of the disease was rapid. Still, it was useful to establish a diagnosis by immunohistochemistry. Since there are no screening tests for pancreatic tumors, it is difficult to identify them in early stages and without gastrointestinal symptoms. [ABSTRACT FROM AUTHOR]

Intraventricular haemorrhage is a common complication of premature birth. Survivors are often left with cerebral palsy, intellectual disability and/or hydrocephalus. Animal models suggest that brain tissue shrinkage, with subsequent vascular stretch and tear, is an important step in the pathophysiology, but the cause of this shrinkage is unknown. Clinical risk factors for intraventricular haemorrhage are biomarkers of hypoxic–ischaemic stress, which causes mature neurons to swell. However, immature neuronal volume might shift in the opposite direction in these conditions. This is because immature neurons express the chloride, salt and water transporter NKCC1, which subserves regulatory volume increases in non-neural cells, whereas mature neurons express KCC2, which subserves regulatory volume decreases. When hypoxic–ischaemic conditions reduce active ion transport and increase the cytoplasmic membrane permeability, the effects of these transporters are diminished. Consequentially, mature neurons swell (cytotoxic oedema), whereas immature neurons might shrink. After hypoxic–ischaemic stress, in vivo and in vitro multi-photon imaging of perinatal transgenic mice demonstrated shrinkage of viable immature neurons, bulk tissue shrinkage and blood vessel displacement. Neuronal shrinkage was correlated with age-dependent membrane salt and water transporter expression using immunohistochemistry. Shrinkage of immature neurons was prevented by prior genetic or pharmacological inhibition of NKCC1 transport. These findings open new avenues of investigation for the detection of acute brain injury by neuroimaging, in addition to prevention of neuronal shrinkage and the ensuing intraventricular haemorrhage, in premature infants. [ABSTRACT FROM AUTHOR]

Objectives To determine the role of keratin 17 (K17) as a predictive biomarker for response to chemotherapy by defining thresholds of K17 expression based on immunohistochemical tests that could be used to optimize therapeutic intervention for patients with pancreatic ductal adenocarcinoma (PDAC). Methods We profiled K17 expression, a hallmark of the basal molecular subtype of PDAC, by immunohistochemistry in 2 cohorts of formalin-fixed, paraffin-embedded PDACs (n = 305). We determined a K17 threshold of expression to optimize prognostic stratification according to the lowest Akaike information criterion and explored the potential relationship between K17 and chemoresistance by multivariate predictive analyses. Results Patients with advanced-stage, low K17 PDACs treated using 5-fluorouracil (5-FU)–based chemotherapeutic regimens had 3-fold longer survival than corresponding cases treated with gemcitabine-based chemotherapy. By contrast, PDACs with high K17 did not respond to either regimen. The predictive value of K17 was independent of tumor mutation status and other clinicopathologic variables. Conclusions The detection of K17 in 10% or greater of PDAC cells identified patients with shortest survival. Among patients with low K17 PDACs, 5-FU–based treatment was more likely than gemcitabine-based therapies to extend survival. [ABSTRACT FROM AUTHOR]

Objectives Measurable residual disease flow cytometry (MRD-FC) and molecular studies are the most sensitive methods for detecting residual malignant populations after therapy for TP53 -mutated acute myeloid leukemia and myelodysplastic neoplasms (TP53+ AML/MDS). However, their sensitivity is limited in suboptimal aspirates or when the immunophenotype of the neoplastic blasts overlaps with erythroids or normal maturing myeloid cells. In this study, we set out to determine if p53 immunohistochemistry (IHC) correlates with MRD-FC and next-generation sequencing (NGS) in the posttherapy setting and to determine the utility of p53 IHC to detect residual disease in the setting of negative or equivocal MRD-FC. Methods We retrospectively identified 28 pre- and posttherapy bone marrow biopsy specimens from 9 patients with TP53+ AML/MDS and a p53 overexpressor phenotype by IHC (strong 3+ staining at initial diagnosis). Next-generation sequencing and/or MRD-FC results were collected for each specimen. Results Using a threshold of more than ten 2-3+ cells in any one 400× field, p53 IHC detected residual disease with a sensitivity of 94% and a specificity of 89%. The threshold used in this study showed a high degree of concordance among 6 blinded pathologists (Fleiss κ = 0.97). Conclusions Our study suggests that p53 IHC can be used as a rapid tool (within 24 hours) to aid in the detection of residual disease that may complement MRD-FC or NGS in cases in which the flow cytometry immunophenotype is equivocal and/or the bone marrow aspirate is suboptimal. [ABSTRACT FROM AUTHOR]

Purpose: Ulcerative colitis (UC) is a serious health problem with increasing morbidity and prevalence worldwide. The pathogenesis of UC is complex, currently believed to be influenced by genetic factors, dysregulation of the host immune system, imbalance in the intestinal microbiota, and environmental factors. Currently, UC is typically managed using aminosalicylates, immunosuppressants, and biologics as adjunctive therapies, with the risk of relapse and development of drug resistance upon discontinuation. Therefore, further research into the pathogenesis of UC and exploration of potential treatment strategies are necessary to improve the quality of life for affected patients. According to previous studies, Lactobacillus paracasei Jlus66 (Jlus66) reduced inflammation and may help prevent or treat UC. Methods: We used dextran sulfate sodium (DSS) to induce a mouse model of UC to assess the effect of Jlus66 on the progression of colitis. During the experiment, we monitored mouse body weight, food and water consumption, as well as rectal bleeding. Hematoxylin-eosin staining was performed to assess intestinal pathological damage. Protein imprinting and immunohistochemical methods were used to evaluate the protein levels of nuclear factor-kappa B (NF-κB), mitogen-activated protein kinase (MAPK), and tight junction (TJ) proteins in intestinal tissues. Fecal microbiota was analyzed based on partial 16S rRNA gene sequencing. Results: Jlus66 supplementation reduced the degree of colon tissue damage, such as colon shortening, fecal occult blood, colon epithelial damage, and weight loss. Supplementation with Jlus66 reduced DSS-induced upregulation of cytokine levels such as TNF-α, IL-1β, and IL-6 (p < 0.05). The NF-κB pathway and MAPK pathway were inhibited, and the expression of TJ proteins (ZO-1, Occludin, and Claudin-3) was upregulated. 16S rRNA sequencing of mouse cecal contents showed that Jlus66 effectively regulated the structure of the intestinal biota. Conclusion: In conclusion, these data indicate that Jlus66 can alter the intestinal biota and slow the progression of UC, providing new insights into potential therapeutic strategies for UC. [ABSTRACT FROM AUTHOR]

The article focuses on evaluating the high frequency of stromal myofibroblasts in odontogenic keratocysts (OKCs) associated with an impacted tooth compared to other odontogenic cysts and pericoronal follicles (PFs). It highlights that OKCs associated with impacted teeth (OKC-a) exhibit a significantly higher number of α-SMA positive cells than those not associated with impacted teeth (OKC-na) and dentigerous cysts (DCs).

Objective: The present study was performed to identify key biomarkers associated with immune cell infiltration in peri‐implantitis through bioinformatic analyses. Methods: Six peri‐implantitis soft tissue samples and six healthy gingiva samples were obtained from GSE106090, and were used to identify immune‐associated differentially expressed genes (DEGs) in peri‐implantitis. The candidate biomarkers associated with immune cell infiltration were examined by immunohistochemical staining. Results: We identified 2089 upregulated and 2173 downregulated genes. Upregulated DEGs were significantly associated with immune response. Ten key candidate biomarkers were identified in the PPI network, including IL1B, TLR2, TLR4, CCL4, CXCL8, IL10, IL6, CD4, CCL3, and PTPRC. The expression level of the 10 genes increased in peri‐implantitis soft tissue samples compared with healthy gingiva samples. The proportion of CD4+ T cells, iTreg, and Tfh in infiltration immune cells increased in peri‐implantitis soft tissue samples and were positively correlated with the expression level of candidate biomarkers TLR4, CCL3, CXCL8, and IL1B. Immunohistochemistry showed that there were more lymphocytes in peri‐implantitis soft tissue samples, with an increased expression level of TLR4, CCL3, CXCL8, and IL1B. Conclusion: Identification of four novel diagnostic biomarkers was helpful for revealing the molecular mechanisms and could serve as a risk predictor for the immune microenvironment in peri‐implantitis. [ABSTRACT FROM AUTHOR]

Objective: Lidocaine, a common local anesthetic in medical practice, exhibits anticancer properties across various tumor types. In this study, we aimed to investigate the effects and mechanisms of lidocaine on oral squamous cell carcinoma. Methods: Cell viability and proliferation were assessed through CCK‐8 and EdU assays. Transwell assays were used to analyze cell migration and invasion. Immunofluorescence assays were conducted to determine MMP9 levels. In vivo tumor growth was evaluated using a tumor xenograft model, and Ki67 and MMP9 levels were determined using immunohistochemistry. N6‐methyladenosine levels were assessed using dot plots and ELISA. mRNA and protein levels were examined through reverse transcription‐quantitative PCR or western blot analysis. The association between IGF2BP2 and caveolin‐1 was validated through RIP and luciferase reporter assays. Results: Lidocaine exhibited suppressive effects on the viability, migration, invasion, and tumor formation of oral squamous cell carcinoma. IGF2BP2 expression correlated with poor survival and was downregulated by lidocaine. Lidocaine reduced caveolin‐1 stability by decreasing IGF2BP2 levels. Caveolin‐1 overexpression partially reversed the suppressive effects of lidocaine on the progression of oral squamous cell carcinoma cells. Conclusion: Lidocaine exerts an anticancer role in oral squamous cell carcinoma via IGF2BP2‐mediated regulation of caveolin‐1 stability. [ABSTRACT FROM AUTHOR]

Chemical communication through olfaction is crucial for fish behaviours, mediating in socio-sexual behaviours as reproduction. Turbot, a flatfish with significant aquaculture production, possesses a well-developed olfactory system from early developmental stages. After metamorphosis, flatfish acquire their characteristic bilateral asymmetry with an ocular side facing the open water column, housing the dorsal olfactory rosette, and a blind side in contact with the sea bottom where the ventral rosette is located. This study aimed to address the existing gap in specific histological, ultrastructural, lectin-histochemical and immunohistochemical studies of the turbot olfactory rosettes and olfactory bulbs. We examined microdissected olfactory organs of adult turbots and premetamorphic larvae by using routine histological staining techniques, and a wide array of lectins and primary antibodies against G-proteins and calcium-binding proteins. We observed no discernible structural variations in the olfactory epithelium between rosettes, except for the dorsal rosette being larger in size compared to the ventral rosette. Additionally, the use of transmission electron microscopy significantly improved the characterization of the adult olfactory epithelium, exhibiting high cell density, small cell size, and a wide diversity of cell types. Moreover, specific immunopositivity in sensory and non-sensory cells provided us of essential information regarding their olfactory roles. The results obtained significantly enriched the scarce morphological and neurochemical information available on the turbot olfactory system, revealing a highly complex olfactory epithelium with distinct features compared to other teleost species, especially with regard to olfactory cell distribution and immunolabelling patterns. [ABSTRACT FROM AUTHOR]

Aims: To develop a standardised, automated protocol for detecting protein gene product 9.5 (PGP9.5) positive intra‐epidermal nerve fibres (IENFs) in skin biopsies, transitioning from the established manual technique to an automated platform. This automated method, although currently intended for research applications, may improve the accessibility of this diagnostic test for small fibre neuropathy in clinical settings. Methods: Skin biopsies (n = 274) from 100 participants (fibromyalgia syndrome n = 62; idiopathic small fibre neuropathy: n = 16; healthy volunteers: n = 22) were processed using an automated immunohistochemistry platform. IENF quantification was performed by blinded examiners, with reliability assessed via a two‐way mixed‐effects model to evaluate inter‐ and intra‐observer variability. Results: The automated staining system reproduced intra‐epidermal nerve fibre density (IENFD) counts consistent with free‐floating sections (mean ± standard deviation: free‐floating: 5.6 ± 3.4 fibres/mm; automated: 5.9 ± 3.2 fibres/mm). A median difference of 0.3 with a lower bound 95% Confidence Interval (CI) at −0.00005 established non‐inferiority against a margin of −0.4 (p =.08). Specifically, the inter‐class correlation coefficient (class denotes consistency in measured observations) was 99% (95% CI: 0.9–1), indicating excellent agreement between free‐floating and automated methods. The inter‐ and intra‐class coefficient between examiners were both 99% (95% CI: 0.9–0.1) for IENFD, demonstrating high reliability using sections stained using the automated method. Interpretation: Automated immunohistochemistry provides high‐throughput reliable and reproducible intra‐epidermal nerve fibre quantification. This method, although currently proof‐of‐concept, for research use only, may be more widely deployed in histopathology laboratories to increase the adoption of IENFD assessment for the diagnosis of peripheral neuropathies. [ABSTRACT FROM AUTHOR]

Background and Aims: The goal of this study was to define basic constituents of the adult peripheral nervous system (PNS) using intact human nerve tissues. Methods: We combined fluorescent and chromogenic immunostaining methods, myelin‐selective fluorophores, and routine histological stains to identify common cellular and noncellular elements in aldehyde‐fixed nerve tissue sections. We employed Schwann cell (SC)‐specific markers, such as S100β, NGFR, Sox10, and myelin protein zero (MPZ), together with axonal, extracellular matrix (collagen IV, laminin, fibronectin), and fibroblast markers to assess the SC's relationship to myelin sheaths, axons, other cell types, and the acellular environment. Results: Whereas S100β and Sox10 revealed mature SCs in the absence of other stains, discrimination between myelinating and non‐myelinating (Remak) SCs required immunodetection of NGFR along with axonal and/or myelin markers. Surprisingly, our analysis of NGFR+ profiles uncovered the existence of at least 3 different novel populations of NGFR+/S100β− cells, herein referred to as nonglial cells, residing in the stroma and perivascular areas of all nerve compartments. An important proportion of the nerve's cellular content, including circa 30% of endoneurial cells, consisted of heterogenous S100β negative cells that were not associated with axons. Useful markers to identify the localization and diversity of nonglial cell types across different compartments were Thy1, CD34, SMA, and Glut1, a perineurial cell marker. Interpretation: Our optimized methods revealed additional detailed information to update our understanding of the complexity and spatial orientation of PNS‐resident cell types in humans. [ABSTRACT FROM AUTHOR]

Background: Hypersensitivity reactions (HR) are common in mastocytosis. However, little is known about triggers and risk factors. The registry of the European Competence Network on Mastocytosis (ECNM) enables reliable studies in a larger cohort of mastocytosis patients. We assessed prevalence, triggers and risk factors of HR in adults with mastocytosis in the ECNM registry. Methods: Data were collected in 27 ECNM centers. We analyzed potential triggers (Hymenoptera venoms, food, drug, inhalant and others) and risk factors at diagnosis and during follow‐up. The study group consisted of 2485 adults with mastocytosis, 1379 women (55.5%) and 1106 men (44.5%). Median age was 48.2 years (range 18–91 years). Results: Nine hundred and forty eight patients (38.1%) reported one or more HR'. Most common triggers were Hymenoptera venoms in cutaneous mastocytosis (CM) and indolent systemic mastocytosis (ISM), whereas in advanced SM (advSM), most common elicitors were drugs, including nonsteroidal anti‐inflammatory agents and penicillin. In multivariate analyses, tryptase level < 90 ng/mL, <15% infiltration by mast cells in bone marrow biopsy‐sections, and diagnosis of ISM were identified as independent risk factors for HR. For drug‐induced HR, prominent risk factors were advSM and high tryptase levels. New reactions were observed in 4.8% of all patients during 4 years follow‐up. Conclusions: HR are mainly triggered by Hymenoptera venoms in patients with CM and ISM and by drugs in patients with advSM. Tryptase levels <90 ng/mL, mast cell bone marrow infiltration <15%, and WHO category ISM are predictors of HR. New HR occur in 4.8% of all patients within 4 years. [ABSTRACT FROM AUTHOR]

Purpose: In a population‐based cohort of 960 uveal melanoma (UM) patients, we describe patients with three additional malignancies, including one unique patient with four synchronous primary malignancies. Method: A descriptive presentation of the clinical course and outcome for UM patients with three additional primary malignancies. Results: After more than 20 years of follow‐up of the UM cohort, 11 patients (1.1%) were diagnosed with three additional primary malignancies before, simultaneously or after UM. Among these, one patient had four synchronous primary malignancies, detected during workup for a symptomatic UM. All diagnoses were treated during the following 4 months, firstly the breast cancer, thereafter, the lung and pancreatic cancers and finally the UM. The patient died 3 years later of abdominal carcinomatosis due to the pancreatic cancer. The family history and gene testing did not disclose any genetic predisposition for cancer. A comparison of the four synchronous tumours, morphologically and immunohistochemically, showed no similarities and the expression of antibodies was different. Conclusion: Patients with UM may be diagnosed with non‐ocular additional primary cancers. Thus, a comprehensive workup is obligatory and a further follow‐up of the UM patients seems necessary. The UM is not always the main problem. [ABSTRACT FROM AUTHOR]

Fifteen percent of all colorectal cancers have detectable defects in the mismatch repair system (dMMR). MMR status is used to identify possible Lynch Syndrome (LS) and to determine prognosis and choice of treatment. Two standard techniques for determining MMR status are immunohistochemistry (IHC) and analysis for microsatellite instability (MSI) by PCR. Recently, our department introduced Idylla™ MSI assay as an alternative option to IHC, and as part of this, we introduced a decision algorithm. The purpose of this study was to review the use of the new method and our algorithm and to assess possible false‐positive results. Retrospectively, we identified 629 cases of colorectal cancer in which either IHC (336 cases) or Idylla™ MSI (293 cases) was performed. Similar results were obtained by the two methods. IHC detected dMMR in 55 cases (16%) and Idylla™ MSI in 52 cases (18%). In all 52 cases of MSI, subsequent IHC was performed. One case was not confirmed by IHC, but was confirmed by another PCR‐based method. Overall, we found that the Idylla™ MSI works well as a screening method for dMMR with no false‐positive cases detected. The proposed algorithm was useful and easily applicable. [ABSTRACT FROM AUTHOR]

Objective: The objective is to characterize transcriptomic profiles and immune cell composition and distribution in juvenile idiopathic arthritis (JIA) synovial biopsies, assess for associations of these features with clinical parameters, and compare JIA and rheumatoid arthritis (RA) synovial features. Methods: RNA sequencing (RNASeq) was performed on 24 samples, with pathway analysis and inference of relative abundance of immune cell subsets based on gene expression data. Two multiplex fluorescence immunohistochemistry (IHC) panels were performed on 28 samples (including 13 on which RNASeq was performed), staining for CD206− classical and CD206+ nonclassical macrophages, and CD8+ and CD4+ T and B lymphocytes. Data were compared to a published series of early RA synovial biopsies. Results: Pathway analysis of the most variably expressed genes (n = 339) identified a B and plasma cell signature as the main driver of heterogeneity in JIA synovia, with strong overlap between JIA and RA synovitis. Multiplex IHC confirmed heterogeneity of immune cell infiltration. M1‐like macrophage–rich synovial lining was associated with greater lining hypertrophy and higher (CD45+) pan–immune cell and CD8+ T cell infiltration. Conclusion: Our study indicates significant similarities between JIA and RA synovitis. Similar to RA, JIA synovia may be broadly categorized into two groups: (1) those with an inflammatory/adaptive immune transcriptomic signature, M1‐like macrophage and CD8+ T cell infiltration, and thicker, M1‐like macrophage–rich synovial lining, and (2) those with an M2‐like macrophage transcriptomic signature, greater M2/M1‐like macrophage ratios, and thinner, M2‐like macrophage–rich synovial lining. Synovial features were not significantly associated with clinical parameters, likely because of group size and heterogeneity. [ABSTRACT FROM AUTHOR]

Vitamin D is an essential molecule for cellular homeostasis, playing a critical role in cell fate decisions including cell proliferation, differentiation, and viability. Accumulating evidence has revealed that expression of the vitamin D-metabolizing enzyme CYP24A1 is dysregulated in different types of human malignancy. CYP24A1 has been shown to be involved in the oncogenic property of a variety of carcinoma cells. However, the pathological relevance of CYP24A1 expression level in human oral malignancy remains to be clarified. In the present study, suppression of CYP24A1 expression in oral squamous cell carcinoma (OSCC) cells increased cell proliferation, invasive activity, colony formation efficacy, and tumor growth in vivo. In addition, knockout of CYP24A1 expression inhibited cell death induced by two different types of anticancer drugs, i.e., fluorouracil and cisplatin. Gene clustering by RNA-sequence analysis revealed that several signaling molecules associated with MYC are involved in CYP24A1-mediated oncogenic behaviors. Furthermore, decreased expression level of CYP24A1 was observed in 124/204 cases (61%) of OSCC and was shown to be associated with short relapse-free and overall survival periods. The results showed that a low expression level of CYP24A1 promotes the oncogenic activity of OSCC and is significantly associated with poor prognosis in patients with this malignancy. [ABSTRACT FROM AUTHOR]

Aims: Over 50% of breast cancer cases are "Human epidermal growth factor receptor 2 (HER2) low breast cancer (BC)", characterized by HER2 immunohistochemistry (IHC) scores of 1+ or 2+ alongside no amplification on fluorescence in situ hybridization (FISH) testing. The development of new anti‐HER2 antibody‐drug conjugates (ADCs) for treating HER2‐low breast cancers illustrates the importance of accurately assessing HER2 status, particularly HER2‐low breast cancer. In this study we evaluated the performance of a deep‐learning (DL) model for the assessment of HER2, including an assessment of the causes of discordances of HER2‐Null between a pathologist and the DL model. We specifically focussed on aligning the DL model rules with the ASCO/CAP guidelines, including stained cells' staining intensity and completeness of membrane staining. Methods and Results: We trained a DL model on a multicentric cohort of breast cancer cases with HER2‐IHC scores (n = 299). The model was validated on two independent multicentric validation cohorts (n = 369 and n = 92), with all cases reviewed by three senior breast pathologists. All cases underwent a thorough review by three senior breast pathologists, with the ground truth determined by a majority consensus on the final HER2 score among the pathologists. In total, 760 breast cancer cases were utilized throughout the training and validation phases of the study. The model's concordance with the ground truth (ICC = 0.77 [0.68–0.83]; Fisher P = 1.32e‐10) is higher than the average agreement among the three senior pathologists (ICC = 0.45 [0.17–0.65]; Fisher P = 2e‐3). In the two validation cohorts, the DL model identifies 95% [93% ‐ 98%] and 97% [91% ‐ 100%] of HER2‐low and HER2‐positive tumours, respectively. Discordant results were characterized by morphological features such as extended fibrosis, a high number of tumour‐infiltrating lymphocytes, and necrosis, whilst some artefacts such as nonspecific background cytoplasmic stain in the cytoplasm of tumour cells also cause discrepancy. Conclusion: Deep learning can support pathologists' interpretation of difficult HER2‐low cases. Morphological variables and some specific artefacts can cause discrepant HER2‐scores between the pathologist and the DL model. [ABSTRACT FROM AUTHOR]

Background: Adenoid cystic carcinoma is a rare subtype of triple‐negative breast carcinoma. These low‐grade tumours, which are treated by simple mastectomy and have an excellent prognosis compared to other triple‐negative breast carcinomas. Solid‐variant adenoid cystic carcinomas have basaloid features and are difficult to distinguish morphologically from other triple‐negative breast cancers. Breast adenoid cystic carcinoma exhibits MYB protein overexpression, which can be detected by immunohistochemistry (IHC). Aim: We compared the IHC expression of MYB in solid‐variant adenoid cystic carcinoma with that in other triple‐negative breast cancers. Methods: We conducted IHC staining of 210 samples of triple‐negative breast cancers, including solid‐variant adenoid cystic carcinoma (n = 17), metaplastic breast carcinoma (n = 44), basaloid triple‐negative breast cancer (n = 21), and other triple‐negative invasive ductal carcinoma (n = 128). We classified nuclear staining of MYB as diffuse/strong (3+), focal moderate (2+), focal weak (1+), or none (0). Results: All 17 solid/basaloid adenoid cystic carcinoma cases exhibited 3+ MYB expression. Of the 21 solid/basaloid triple‐negative breast cancers, one (5%) had 2+ expression, seven (33%) 1+ expression, and 13 (62%) 0 expression. Of the 44 metaplastic carcinoma cases, 39 cases (89%) had no (0) staining, and the other five cases had focal weak (1+) or moderate (2+) staining. Among the 128 triple‐negative invasive ductal carcinoma cases, 92 cases (72%) had no (0) staining, 36 cases (28%) exhibited focal weak (1+) or moderate (2+) staining. Conclusions: Our study revealed diffuse/strong MYB staining (3+) only in solid/basaloid adenoid cystic carcinomas. Thus, we recommend routine MYB IHC staining in triple‐negative breast carcinoma with solid/basaloid morphology to improve diagnostic accuracy. [ABSTRACT FROM AUTHOR]

Aims: Human epidermal growth factor receptor 2 (HER2) expression is an important biomarker in breast cancer (BC). Most BC cases categorised as HER2‐negative (HER2−) express low levels of HER2 [immunohistochemistry (IHC) 1+ or IHC 2+/in‐situ hybridisation not amplified (ISH−)] and represent a clinically relevant therapeutic category that is amenable to targeted therapy using a recently approved HER2‐directed antibody–drug conjugate. A group of practising pathologists, with expertise in breast pathology and BC biomarker testing, outline best practices and guidance for achieving consensus in HER2 IHC scoring for BC. Methods and results: The authors describe current knowledge and challenges of IHC testing and scoring of HER2‐low expressing BC and provide best practices and guidance for accurate identification of BCs expressing low levels of HER2. These expert pathologists propose an algorithm for assessing HER2 expression with validated IHC assays and incorporate the 2023 American Society of Clinical Oncology and College of American Pathologist guideline update. The authors also provide guidance on when to seek consensus for HER2 IHC scoring, how to incorporate HER2‐low into IHC reporting and present examples of HER2 IHC staining, including challenging cases. Conclusions: Awareness of BC cases that are negative for HER protein overexpression/gene amplification and the related clinical relevance for targeted therapy highlight the importance of accurate HER2 IHC scoring for optimal treatment selection. [ABSTRACT FROM AUTHOR]

Human epidermal growth factor receptor 2 (HER2)‐enriched breast cancer benefits significantly from anti‐HER2 targeted therapies. This highlights the critical need for precise HER2 immunohistochemistry (IHC) interpretation serving as a triage tool for selecting patients for anti‐HER2 regimens. Recently, the emerging eligibility of patients with HER2‐low breast cancers for a novel HER2‐targeted antibody–drug conjugate (T‐DXd) adds challenges to HER2 IHC scoring interpretation, notably in the 0–1+ range, which shows high interobserver and interlaboratory staining platform variability. In this review, we navigate evolving challenges and suggest practical recommendations for HER2 IHC interpretation. [ABSTRACT FROM AUTHOR]

C2 photosynthesis is a photosynthetic pathway in which photorespiratory CO2 release and refixation are enhanced in leaf bundle sheath (BS) tissues. The evolution of C2 photosynthesis has been hypothesized to be a major step in the origin of C4 photosynthesis, highlighting the importance of studying C2 evolution. In this study, physiological, anatomical, ultrastructural, and immunohistochemical properties of leaf photosynthetic tissues were investigated in six non‐C4Tribulus species and four C4Tribulus species. At 42°C, T. cristatus exhibited a photosynthetic CO2 compensation point in the absence of respiration (C*) of 21 µmol mol−1, below the C3 mean C* of 73 µmol mol−1. Tribulus astrocarpus had a C* value at 42°C of 55 µmol mol−1, intermediate between the C3 species and the C2T. cristatus. Glycine decarboxylase (GDC) allocation to BS tissues was associated with lower C*. Tribulus cristatus and T. astrocarpus allocated 86% and 30% of their GDC to the BS tissues, respectively, well above the C3 mean of 11%. Tribulus astrocarpus thus exhibits a weaker C2 (termed sub‐C2) phenotype. Increased allocation of mitochondria to the BS and decreased length‐to‐width ratios of BS cells, were present in non‐C4 species, indicating a potential role in C2 and C4 evolution. Summary statement: Physiological, structural, and immunohistochemical analyses of leaf tissues indicate sub‐C2 and C2 character states occurring in Tribulus (Zygophyllaceae). These data reveal novel insights into the mechanisms by which photorespiratory CO2 refixation facilitates the evolution of C4 photosynthesis. [ABSTRACT FROM AUTHOR]

Background: Large language model (LLM)‐powered chatbots such as ChatGPT have numerous applications. However, their effectiveness in dermatopathology has not been formally evaluated. Dermatopathological cases often require immunohistochemical workup. Here, we evaluate the performance of a chatbot in providing diagnostically useful information on immunohistochemistry relating to dermatological diseases. Methods: We queried a commonly used chatbot for the immunophenotypes of 51 cutaneous diseases, including a diverse variety of epidermal, adnexal, hematolymphoid, and soft tissue entities. We requested it to provide references for each diagnosis. All tests were repeated, compiled, quantified, and then compared with established literature standards. Results: Clustering analysis demonstrated that recommendations correlated with tumor type, suggesting chatbots can supply appropriate panels. However, a significant portion of recommendations were factually incorrect (13.9%). Citations were rarely clinically useful (24.5%). Many were confabulated (27.2%). Prompt responses for cutaneous adnexal lesions tended to be less accurate while literature references were less useful. Reference retrieval performance was associated with the number of PubMed entries per entity. Conclusions: This foundational study suggests that LLM‐powered chatbots may be useful for generating immunohistochemical panels for dermatologic diagnoses. However, specific performance capabilities and biases must be considered. In addition, extreme caution is advised regarding the tendencies to fabricate material. Future models intentionally fine‐tuned to augment diagnostic medicine may prove to be valuable. [ABSTRACT FROM AUTHOR]

Immune checkpoint inhibitor therapy can provide significant clinical benefit in patients with certain cancer types including melanoma; however, objective responses are only observed for a subset of patients. Mucosal melanoma is a rare melanoma subtype associated with a poor prognosis and, compared with cutaneous melanoma, is significantly less responsive to immune checkpoint inhibitors. Spontaneous canine tumours have emerged as valuable models to inform human cancer studies. In contrast to human melanoma, most canine melanomas are mucosal—an incidence that may be leveraged to better understand the subtype in humans. However, a more comprehensive understanding of the immune landscape of the canine disease is required. Here, we quantify tumour infiltrative T and myeloid cells in canine mucosal (n = 13) and cutaneous (n = 5) melanomas using immunohistochemical analysis of CD3 and MAC387 expression, respectively. Gene expression analysis using the Canine IO NanoString panel was also performed to identify genes and pathways associated with immune cell infiltration. T and myeloid cell densities were variable with geometric means of 158.7 cells/mm2 and 166.7 cells/mm2, respectively. Elevated T cell infiltration was associated with increased expression of cytolytic genes as well as genes encoding the coinhibitory checkpoint molecules PD‐1, CTLA‐4, TIM‐3 and TIGIT; whereas increased myeloid cell infiltration was associated with elevated expression of protumourigenic cytokines. These data provide a basic characterization of the tumour microenvironment of canine malignant melanoma and suggest that, like human melanoma, inherent variability in anti‐tumour T cell responses exists and that a subset of canine melanomas may respond better to immunomodulation. [ABSTRACT FROM AUTHOR]

Matrix metalloproteinase-9 (MMP-9) is involved in tissue remodeling and in skin wound healing. The present study focuses on the MMP-9 expression in epidermal wound healing within 1 h after injury, to test whether MMP-9 can be used to estimate the time of injury in forensic practice. A sample consisting of 5 individuals undergoing surgery was analyzed. With the consent of the patients, sections of skin were removed from the surgical wound at predefined time intervals. For each subject, 8 sections were taken, one for each time interval defined at 0 '- 1' − 3 '- 5' − 10 '- 15' − 30 '- 60' minutes. The specimens were immunostained with MMP-9, and the number of positively stained cells was examined. The number of positively stained cells showed an increasing trend as a function of time. Less than 30 positively stained cells were found in all cases within 3 min. At the post-infliction time of 5 min, the number of positively stained cells exceeded 30 in 3 out of 5 cases. The number of MMP-positive cells exceeded 40 in all cases in over 10 min. In the light of these results, the count of MMP-9 positive cells might be a useful marker in the wound-age estimation within 1 h in forensic setting. More research is required to collect more samples and to compare samples from the hyperacute phase with those from several days after injury. [ABSTRACT FROM AUTHOR]

Eosinophilic esophagitis (EoE) and gastroesophageal reflux disease (GERD) share many histopathological features; therefore, markers for differentiation are of diagnostic interest and may add to the understanding of the underlying mechanisms. The nitrergic system is upregulated in GERD and probably also in EoE. Esophageal biopsies of patients with EoE (n  = 20), GERD (n  = 20), and healthy volunteers (HVs) (n  = 15) were exposed to antibodies against inducible nitric oxide synthase (iNOS), nitrotyrosine, eosinophilic peroxidase, eotaxin-3, and galectin-3. The stained object glasses were randomized, digitized, and blindly analyzed regarding the expression of DAB (3,3′-diaminobenzidine) by a protocol developed in QuPath software. A statistically significant overexpression of iNOS was observed in patients with any of the two inflammatory diseases compared with that in HVs. Eotaxin-3 could differentiate HVs versus inflammatory states. Gastroesophageal reflux patients displayed the highest levels of nitrotyrosine. Neither iNOS nor nitrotyrosine alone were able to differentiate between the two diseases. For that purpose, eosinophil peroxidase was a better candidate, as the mean levels increased stepwise from HVs via GERD to EoE. iNOS and nitrotyrosine are significantly overexpressed in patients with EoE and GERD compared with healthy controls, but only eosinophil peroxidase could differentiate the two types of esophagitis. The implications of the finding of the highest levels of nitrotyrosine among gastroesophageal reflux patients are discussed. [ABSTRACT FROM AUTHOR]