Deciphering the role of ferroptosis in rheumatoid arthritis: Synovial transcriptome analysis and immune infiltration correlation.

The pathogenesis of rheumatoid arthritis (RA) remains elusive. The initiation of joint degeneration is characterized by the loss of self-tolerance in peripheral joints. Ferroptosis, a form of regulated cell death, holds significant importance in the pathophysiology of inflammatory arthritis, primarily due to iron accumulation and the subsequent lipid peroxidation. The present study investigated the association between synovial lesions and ferroptosis-related genes using previously published data from rheumatoid patients. Transcriptome differential gene analysis was employed to identify ferroptosis-related differentially expressed genes (FRDEGs). To validate FRDEGs and screen hub genes, we used weighted gene co-expression network analysis (WGCNA) and receiver operating characteristic (ROC) curves. Subsequently, immune infiltration analysis and single cell analysis were conducted to investigate the relationship between various synovial tissues cells and FRDEGs. The findings were further confirmed through reverse transcription-quantitative polymerase chain reaction (RT-qPCR), immunohistochemical staining, and immunofluorescence techniques. Upon intersecting DEGs with ferroptosis-related genes, we identified a total of 104 FRDEGs. Through the construction of a protein-protein interaction (PPI) network, we pinpointed the top 20 most highly concentrated genes as hub genes. Subsequent analyses using ROC curve and WGCNA validated eight FRDEGs: TIMP1, JUN, EGFR, SREBF1, ADIPOQ, SCD, AR, and FABP4. Immuno-infiltration analyses revealed significant infiltration of immune cell in RA synovial tissues and their correlations with the FRDEGs. Notably, TIMP1 demonstrated a positive correlation with various immune cell populations. Single-cell sequencing date of RA synovial tissue revealed predominant expression of TIMP1 is in fibroblasts. RT-qPCR, immunohistochemistry, and immunofluorescence analyses confirmed significant upregulation of TIMP1 at both mRNA and protein levels in RA synovial tissues and fibroblast-like synoviocytes (FLS). The findings provide novel insights into pathophysiology of peripheral immune tolerance deficiency in RA. The dysregulation of TIMP1, a gene associated with ferroptosis, was significantly observed in RA patients, suggesting its potential as a promising biomarker and therapeutic target.

Culture-negative infective endocarditis due to Neisseria bacilliformis identified via 16S rRNA gene analysis from resected valve tissue: Case report and review of the literature.

Blood culture-negative infective endocarditis (BCNE) has a poorer prognosis than culture-positive cases. Thus, it is crucial to determine the pathogenic microorganism using molecular diagnostic techniques, in addition to conventional techniques, including cultures of blood and/or resected valve tissue. Herein, we report a case of culture-negative infective endocarditis (IE) caused by Neisseria bacilliformis, as identified by 16S rRNA analysis of valve tissue. N. bacilliformis a non-gonococcal and non-meningococcal Neisseria species that partially comprises the oropharyngeal microbiome, and reports of invasive infections have increased recently. We conducted a literature review of IE caused by N. bacilliformis and found that beta-lactam antibiotics were effective with a relatively favorable prognosis. To the best of our knowledge, this is the first case of culture-negative IE in which N. bacilliformis was identified via 16S rRNA analysis.

NOX4-mediated astrocyte ferroptosis in Alzheimer's disease.

This study investigates NADPH oxidase 4 (NOX4) involvement in iron-mediated astrocyte cell death in Alzheimer's Disease (AD) using single-cell sequencing data and transcriptomes. We analyzed AD single-cell RNA sequencing data, identified astrocyte marker genes, and explored biological processes in astrocytes. We integrated AD-related chip data with ferroptosis-related genes, highlighting NOX4. We validated NOX4's role in ferroptosis and AD in vitro and in vivo. Astrocyte marker genes were enriched in AD, emphasizing their role. NOX4 emerged as a crucial player in astrocytic ferroptosis in AD. Silencing NOX4 mitigated ferroptosis, improved cognition, reduced Aß and p-Tau levels, and alleviated mitochondrial abnormalities. NOX4 promotes astrocytic ferroptosis, underscoring its significance in AD progression.

Diversity and structure of the deep-sea sponge microbiome in the equatorial Atlantic Ocean.

Sponges (phylum Porifera) harbour specific microbial communities that drive the ecology and evolution of the host. Understanding the structure and dynamics of these communities is emerging as a primary focus in marine microbial ecology research. Much of the work to date has focused on sponges from warm and shallow coastal waters, while sponges from the deep ocean remain less well studied. Here, we present a metataxonomic analysis of the microbial consortia associated with 23 individual deep-sea sponges. We identify a high abundance of archaea relative to bacteria across these communities, with certain sponge microbiomes comprising more than 90 % archaea. Specifically, the archaeal family Nitrosopumilaceae is prolific, comprising over 99 % of all archaeal reads. Our analysis revealed that sponge microbial communities reflect the host sponge phylogeny, indicating a key role for host taxonomy in defining microbiome composition. Our work confirms the contribution of both evolutionary and environmental processes to the composition of microbial communities in deep-sea sponges.

Effects of Selenium Content on Growth, Antioxidant Activity, and Key Selenium-Enriched Gene Expression in Alfalfa Sprouts.

To enhance the selenium (Se) intake of the general public, the present study implemented biofortification techniques in alfalfa sprouts. Alfalfa sprouts possess unique nutritional value and provide an optimal Se-enriched supplemental Se source. The impact of sodium selenite (Na2SeO3) on alfalfa shoot germination, shoot length, and biomass was assessed experimentally, and changes in the antioxidant capacity of sprouts treated with optimal Se concentrations were investigated. In addition, the transcriptome of alfalfa sprouts treated with the optimal Na2SeO3 concentration was sequenced. Gene co-expression networks, constructed through differential gene analysis and weighted gene co-expression network analysis, were used to identify the core genes responsible for Se enrichment in alfalfa sprouts. The findings of the present study offer novel insights into the effects of Se treatment on the nutrient composition of alfalfa sprouts, in addition to introducing novel methods and references that could facilitate production of Se-enriched alfalfa sprouts and associated products.

Fluorometric determination of mecA gene in MRSA with a graphene-oxide based bioassay using flap endonuclease 1-assisted target recycling and Klenow fragment-triggered signal amplification.

Methicillin-resistant Staphylococcus aureus (MRSA) is a multidrug-resistant bacterium that causes a wide range of illnesses, necessitating the development of new technologies for its detection. Herein, we propose a graphene oxide (GO)-based sensing platform for the detection of mecA gene in MRSA using flap endonuclease 1 (FEN1)-assisted target recycling and Klenow fragment (KF)-triggered signal amplification. Without the target, all the DNA probes were adsorbed onto GO, resulting in fluorescence quenching of the dye. Upon the addition of the target, a triple complex was formed that triggered FEN1-assisted target recycling and initiated two polymerization reactions with the assistance of KF polymerase, generating numerous dsDNA that were repelled by GO. These dsDNAs triggered fluorescence enhancement when SYBR Green I was added. Therefore, the target DNA was quantified by measuring the fluorescence at excitation and emission wavelengths of 480/526 nm. This mecA gene assay showed a good linear range from 1 to 50 nM with a lower limit of detection of 0.26 nM, and displayed good applicability to the analysis of real samples. Thus, a new method for monitoring MRSA has been developed that has great potential for early clinical diagnosis and treatment.

Identification of proteolytic bacteria from Yunnan fermented foods and their use to reduce the allergenicity of ß-lactoglobulin.

Beta-lactoglobulin (ß-LG) is considered to be the major allergenic protein in milk. Lactic acid bacteria (LAB) possess a protein hydrolysis system that holds great promise for hydrolyzing ß-LG and reducing its allergenicity. Therefore, this study aimed to screen LAB with ß-LG hydrolysis activity from Yunnan traditional fermented foods. The results showed that Pediococcus pentosaceus C1001, Pediococcus acidilactici E1601-1, and Lactobacillus paracasei E1601-2, could effectively hydrolyze ß-LG and further reduce its sensitization (more than 40%). All 3 lactic acid bacteria hydrolyzed ß-LG allergenic fragments V41-K60 and L149-I162. Moreover, they encode a variety of genes related to proteolysis, such as aminopeptidase pepC and pepN, proline peptidase pepIP and endopeptidase pepO, and L. paracasei E1601-2 contains extracellular protease coding gene prtP. And they encode a variety of genes associated with hydrolyzed proteins. The 3 strains screened in this study can be used to develop hypoallergenic dairy products.

Genome-Wide Transcriptomic and Metabolomic Analyses Unveiling the Defence Mechanisms of Populus tremula against Sucking and Chewing Insect Herbivores.

Plants and insects coevolved as an evolutionarily successful and enduring association. The molecular arms race led to evolutionary novelties regarding unique mechanisms of defence and detoxification in plants and insects. While insects adopt mechanisms to conquer host defence, trees develop well-orchestrated and species-specific defence strategies against insect herbivory. However, current knowledge on the molecular underpinnings of fine-tuned tree defence responses against different herbivore insects is still restricted. In the current study, using a multi-omics approach, we unveiled the defence response of Populus tremula against aphids (Chaitophorus populialbae) and spongy moths (Lymantria dispar) herbivory. Comparative differential gene expression (DGE) analyses revealed that around 272 and 1203 transcripts were differentially regulated in P. tremula after moth and aphid herbivory compared to uninfested controls. Interestingly, 5716 transcripts were differentially regulated in P. tremula between aphids and moth infestation. Further investigation showed that defence-related stress hormones and their lipid precursors, transcription factors, and signalling molecules were over-expressed, whereas the growth-related counterparts were suppressed in P. tremula after aphid and moth herbivory. Metabolomics analysis documented that around 37% of all significantly abundant metabolites were associated with biochemical pathways related to tree growth and defence. However, the metabolic profiles of aphid and moth-fed trees were quite distinct, indicating species-specific response optimization. After identifying the suitable reference genes in P. tremula, the omics data were further validated using RT-qPCR. Nevertheless, our findings documented species-specific fine-tuning of the defence response of P. tremula, showing conservation on resource allocation for defence overgrowth under aphid and moth herbivory. Such findings can be exploited to enhance our current understanding of molecular orchestration of tree responses against herbivory and aid in developing insect pest resistance P. tremula varieties.

Treatment of high ammonia anaerobically digested molasses wastewater using aerobic granular sludge reactor.

This study addressed the treatment of high ammonia, low biodegradable chemical oxygen demand (bCOD) anaerobically digested molasses wastewater, utilizing an aerobic granular sludge (AGS) reactor. The AGS achieved 99 % ammonia removal regardless of the bCOD supplementation. By adding low ammonia (<60 mg/L), high bCOD raw molasses wastewater (before anaerobic digestion) as a carbon source, enhanced nitrogen removal, increasing from 10 % to 97 %, and improved sludge settleability via bio-induced calcite precipitation were observed. Functional genes prediction suggested two potential denitrification pathways, including heterotrophic denitrification by Paracoccus and Thauera, and autotrophic denitrification, specifically sulfide-oxidizing autotrophic denitrification by Thiobacillus. An increase in the relative abundance of microorganisms involved in heterotrophic denitrification was observed with the addition of high bCOD raw molasses wastewater. Consequently, incorporating raw molasses wastewater into the AGS presents a sustainable approach to achieve mixotrophic denitrification, maintain stable granular sludge and ensure stable treatment performance when treating anaerobically digested molasses wastewater.

A comprehensive workflow for optimizing RNA-seq data analysis.

BACKGROUND: Current RNA-seq analysis software for RNA-seq data tends to use similar parameters across different species without considering species-specific differences. However, the suitability and accuracy of these tools may vary when analyzing data from different species, such as humans, animals, plants, fungi, and bacteria. For most laboratory researchers lacking a background in information science, determining how to construct an analysis workflow that meets their specific needs from the array of complex analytical tools available poses a significant challenge. RESULTS: By utilizing RNA-seq data from plants, animals, and fungi, it was observed that different analytical tools demonstrate some variations in performance when applied to different species. A comprehensive experiment was conducted specifically for analyzing plant pathogenic fungal data, focusing on differential gene analysis as the ultimate goal. In this study, 288 pipelines using different tools were applied to analyze five fungal RNA-seq datasets, and the performance of their results was evaluated based on simulation. This led to the establishment of a relatively universal and superior fungal RNA-seq analysis pipeline that can serve as a reference, and certain standards for selecting analysis tools were derived for reference. Additionally, we compared various tools for alternative splicing analysis. The results based on simulated data indicated that rMATS remained the optimal choice, although consideration could be given to supplementing with tools such as SpliceWiz. CONCLUSION: The experimental results demonstrate that, in comparison to the default software parameter configurations, the analysis combination results after tuning can provide more accurate biological insights. It is beneficial to carefully select suitable analysis software based on the data, rather than indiscriminately choosing tools, in order to achieve high-quality analysis results more efficiently.

Exploring Schizophrenia Classification Through Multimodal MRI and Deep Graph Neural Networks: Unveiling Brain Region-Specific Weight Discrepancies and Their Association With Cell-Type Specific Transcriptomic Features.

BACKGROUND AND HYPOTHESIS: Schizophrenia (SZ) is a prevalent mental disorder that imposes significant health burdens. Diagnostic accuracy remains challenging due to clinical subjectivity. To address this issue, we explore magnetic resonance imaging (MRI) as a tool to enhance SZ diagnosis and provide objective references and biomarkers. Using deep learning with graph convolution, we represent MRI data as graphs, aligning with brain structure, and improving feature extraction, and classification. Integration of multiple modalities is expected to enhance classification. STUDY DESIGN: Our study enrolled 683 SZ patients and 606 healthy controls from 7 hospitals, collecting structural MRI and functional MRI data. Both data types were represented as graphs, processed by 2 graph attention networks, and fused for classification. Grad-CAM with graph convolution ensured interpretability, and partial least squares analyzed gene expression in brain regions. STUDY RESULTS: Our method excelled in the classification task, achieving 83.32% accuracy, 83.41% sensitivity, and 83.20% specificity in 10-fold cross-validation, surpassing traditional methods. And our multimodal approach outperformed unimodal methods. Grad-CAM identified potential brain biomarkers consistent with gene analysis and prior research. CONCLUSIONS: Our study demonstrates the effectiveness of deep learning with graph attention networks, surpassing previous SZ diagnostic methods. Multimodal MRI's superiority over unimodal MRI confirms our initial hypothesis. Identifying potential brain biomarkers alongside gene biomarkers holds promise for advancing objective SZ diagnosis and research in SZ.

Molecular interactions between metformin and D-limonene inhibit proliferation and promote apoptosis in breast and liver cancer cells.

BACKGROUND: Cancer is a fatal disease that severely affects humans. Designing new anticancer strategies and understanding the mechanism of action of anticancer agents is imperative. HYPOTHESIS/PURPOSE: In this study, we evaluated the utility of metformin and D-limonene, alone or in combination, as potential anticancer therapeutics using the human liver and breast cancer cell lines HepG2 and MCF-7. STUDY DESIGN: An integrated systems pharmacology approach is presented for illustrating the molecular interactions between metformin and D-limonene. METHODS: We applied a systems-based analysis to introduce a drug-target-pathway network that clarifies different mechanisms of treatment. The combination treatment of metformin and D-limonene induced apoptosis in both cell lines compared with single drug treatments, as indicated by flow cytometric and gene expression analysis. RESULTS: The mRNA expression of Bax and P53 genes were significantly upregulated while Bcl-2, iNOS, and Cox-2 were significantly downregulated in all treatment groups compared with normal cells. The percentages of late apoptotic HepG2 and MCF-7 cells were higher in all treatment groups, particularly in the combination treatment group. Calculations for the combination index (CI) revealed a synergistic effect between both drugs for HepG2 cells (CI = 0.14) and MCF-7 cells (CI = 0.22). CONCLUSION: Our data show that metformin, D-limonene, and their combinations exerted significant antitumor effects on the cancer cell lines by inducing apoptosis and modulating the expression of apoptotic genes.

Antibiotic-Resistance Profiles and Genetic Diversity of Shigella Isolates in China: Implications for Control Strategies.

The urgent need for comprehensive and systematic analyses of Shigella as the key pathogen led us to meticulously explore the epidemiology and molecular attributes of Shigella isolates. Accordingly, we procured 24 isolates (10 from Xinjiang and 14 from Wuhan, China) and performed serotype identification and antimicrobial susceptibility testing. Resistance gene detection and homology analysis by polymerase chain reaction and pulsed-field gel electrophoresis (PFGE), respectively, were performed for genetic diversity analysis. All isolates were identified as Shigella flexneri, with 70% (35.4-91.9%) and 30% (8.1-64.6%) of the Xinjiang isolates and 85.7% (56.2-97.5%) and 14.3% (2/14, 2.5-43.9%) of the Wuhan isolates belonging to serotype 2a and serotype 2b, respectively. All isolates displayed resistance to at least two antibiotics and complete resistance to ampicillin. Multidrug resistance (MDR) was recorded in 70.8% (48.8-86.6%) of isolates, with Xinjiang isolates exhibiting relatively higher resistance to ampicillin-sulbactam, piperacillin, ceftriaxone, and aztreonam. Conversely, Wuhan isolates displayed higher MDR and resistance to tetracycline, ciprofloxacin, levofloxacin, and cefepime relative to Xinjiang isolates. Molecular scrutiny of antibiotic-resistance determinants revealed that blaTEM was the main mechanism of ampicillin resistance, blaCTX-M was the main gene for resistance to third- and fourth-generation cephalosporins, and tetB was the predominant gene associated with tetracycline resistance. Four Xinjiang and seven Wuhan isolates shared T1-clone types (>85%), and two Xinjiang and one Wuhan isolates were derived from the T6 clone with a high similarity of 87%. Six PFGE patterns (T1, T2, T5, T6-3, T8, and T10) of S. flexneri were associated with MDR. Thus, there is a critical need for robust surveillance and control strategies in managing Shigella infections, along with the development of targeted interventions and antimicrobial stewardship programs tailored to the distinct characteristics of Shigella isolates in different regions of China.

Shared Genetic Features of Psoriasis and Myocardial Infarction: Insights From a Weighted Gene Coexpression Network Analysis.

BACKGROUND: Increasing evidence suggests a higher propensity for acute myocardial infarction (MI) in patients with psoriasis. However, the shared mechanisms underlying this comorbidity in these patients remain unclear. This study aimed to explore the shared genetic features of psoriasis and MI and to identify potential biomarkers indicating their coexistence. METHODS AND RESULTS: Data sets obtained from the gene expression omnibus were examined using a weighted gene coexpression network analysis approach. Hub genes were identified using coexpression modules and validated in other data sets and through in vitro cellular experiments. Bioinformatics tools, including the Human microRNA Disease Database, StarBase, and miRNet databases, were used to construct a ceRNA network and predict potential regulatory mechanisms. By applying weighted gene coexpression network analysis, we identified 2 distinct modules that were significant for both MI and psoriasis. Inflammatory and immune pathways were highlighted by gene ontology enrichment analysis of the overlapping genes. Three pivotal genes-Src homology and collagen 1, disruptor of telomeric silencing 1-like, and feline leukemia virus subgroup C cellular receptor family member 2-were identified as potential biomarkers. We constructed a ceRNA network that suggested the upstream regulatory roles of these genes in the coexistence of psoriasis and MI. CONCLUSIONS: As potential therapeutic targets, Src homology and collagen 1, feline leukemia virus subgroup C cellular receptor family member 2, and disruptor of telomeric silencing 1-like provide novel insights into the shared genetic features between psoriasis and MI. This study paves the way for future studies focusing on the prevention of MI in patients with psoriasis.

Gene Expression Analysis of a Topical Serum Comprised of Plant-based Adaptogens Developed to Support Homeostasis and Skin Quality.

Objective: A topical serum comprised of plant-based adaptogens was purposefully developed to support the ability of the skin to adapt and achieve balance. The study described herein evaluated changes in the expression of target genes related to skin homeostasis following topical exposure. Methods: Utilizing an in vitro epidermal skin model, quantitative polymerase chain reaction (qPCR) analysis of gene expression was conducted following 48-hour exposure to 15µL of the study product (MYS serum) to the surface of each tissue (N=4). Biomarkers that play a key role in skin homeostasis were analyzed: Aryl hydrocarbon receptor (AhR), chloride channel accessory 2 (CLCA2), metallothionein 1A (MT1A), 1F (MT1F), and 1G (MT1G), and thioredoxin reductase 1 (TXNRD1). Statistically significant changes were calculated using unpaired t-test analysis (p<0.05) versus control (saline). A linear Fold Change (FC) value >2 was considered statistically significant. Results: An 85 percent (FC=1.85) increase in expression of AhR vs. control occurred following exposure to MYS serum indicating enhanced support of cellular and epidermal homeostasis, and the skin barrier's response to stress. Statistically significant increases in expression occurred with TXNRD1 (293%; FC=3.93), MT1A (307%; FC=4.07), MT1F (529%; FC=6.29), and MT1G (163%; FC=12.63) vs. control, indicating support of skin's adaptive response to stress and immune homeostasis. Significantly decreased levels of CLCA2 were demonstrated (69%; FC=-3.24) indicating inhibition of oxidative stress-induced senescence. Conclusion: Utilizing an in vitro epidermal skin model, a serum comprised of plant-based adaptogens demonstrated changes in the expression of target genes that play important roles in skin's ability to respond to stress and achieve homeostasis.

Development of a Novel Endometrial Signature Based on Endometrial microRNA for Determining the Optimal Timing for Embryo Transfer.

Though tremendous advances have been made in the field of in vitro fertilization (IVF), a portion of patients are still affected by embryo implantation failure issues. One of the most significant factors contributing to implantation failure is a uterine condition called displaced window of implantation (WOI), which refers to an unsynchronized endometrium and embryo transfer time for IVF patients. Previous studies have shown that microRNAs (miRNAs) can be important biomarkers in the reproductive process. In this study, we aim to develop a miRNA-based classifier to identify the WOI for optimal time for embryo transfer. A reproductive-related PanelChip® was used to obtain the miRNA expression profiles from the 200 patients who underwent IVF treatment. In total, 143 out of the 167 miRNAs with amplification signals across 90% of the expression profiles were utilized to build a miRNA-based classifier. The microRNA-based classifier identified the optimal timing for embryo transfer with an accuracy of 93.9%, a sensitivity of 85.3%, and a specificity of 92.4% in the training set, and an accuracy of 88.5% in the testing set, showing high promise in accurately identifying the WOI for the optimal timing for embryo transfer.

Intracanal microbiome profiles of two apical periodontitis cases in one patient: A comparison with saliva and plaque profiles.

OBJECTIVES: To determine the characteristics of the endodontic microbiome. MATERIAL AND METHODS: Saliva, plaque, and infected root canal wall dentin of two teeth suffering from apical periodontitis were harvested from a 58-year-old man. Bacterial DNA was extracted from each sample, and 16S rRNA gene analysis targeting the V3-V4 region was conducted on the Illumina MiSeq platform using QIIME2. The functional potential of the microbiomes was inferred using PICRUSt2. RESULTS: The four microbiomes were different in structure and membership, yet the nine most abundant metabolic pathways were common among them. The two endodontic microbiomes were more anaerobic, rich in Firmicutes, and scarce in Actinobacteriota and Proteobacteria, compared with saliva and plaque microbiomes. Their profiles were dissimilar despite their clinical and radiographic similarities. CONCLUSIONS: The endodontic microbiomes were anaerobic, rich in Firmicutes, scarce in Actinobacteriota and Proteobacteria, and considerably varied within an individual.

Comprehensive Treatment and Gene Analysis of a Male Patient with Follicular Occlusion Tetrad with Fordyce Granules.

Follicular occlusion tetrad (FOT) is a chronic inflammatory skin disease that seriously affects patients' quality of life. At present, there is no standard treatment plan for FOT. We report the case of a 50-year-old male patient diagnosed as having FOT with Fordyce granules and type 2 diabetes mellitus. During hospitalization, the patient received comprehensive and systematic treatment. The patient healed well after surgery and the 10-month follow-up revealed no recurrence. We found eight gene mutations by whole-exome sequencing (WES) of the patient's peripheral blood.

Small cell osteosarcoma versus fusion-driven round cell sarcomas of bone: retrospective clinical, radiological, pathological, and (epi)genetic comparison with clinical implications.

Small cell osteosarcoma (SCOS), a variant of conventional high-grade osteosarcoma (COS), may mimic fusion-driven round cell sarcomas (FDRCS) by overlapping clinico-radiological and histomorphological/immunohistochemical characteristics, hampering accurate diagnosis and consequently proper therapy. We retrospectively analyzed decalcified formalin-fixed paraffin-embedded (FFPE) samples of 18 bone tumors primarily diagnosed as SCOS by methylation profiling, fusion gene analysis, and immunohistochemistry.In eight cases, the diagnosis of SCOS was maintained, and in 10 cases it was changed into FDRCS, including three Ewing sarcomas (EWSR1::FLI1 in two cases and no identified fusion gene in the third case), two sarcomas with BCOR alterations (KMT2D::BCOR, CCNB3::BCOR, respectively), three mesenchymal chondrosarcomas (HEY1::NCOA2 in two cases and one case with insufficient RNA quality), and two sclerosing epithelioid fibrosarcomas (FUS::CREBL3 and EWSR1 rearrangement, respectively).Histologically, SCOS usually possessed more pleomorphic cells in contrast to the FDRCS showing mainly monomorphic cellular features. However, osteoid was seen in the latter tumors as well, often associated with slight pleomorphism. Also, the immunohistochemical profile (CD99, SATB2, and BCOR) overlapped.Clinically and radiologically, similarities between SCOS and FDRCS were observed, with by imaging only minimal presence or lack of (mineralized) osteoid in most of the SCOSs.In conclusion, discrimination of SCOS, epigenetically related to COS, versus FDRCS of bone can be challenging but is important due to different biology and therefore therapeutic strategies. Methylation profiling is a reliable and robust diagnostic test especially on decalcified FFPE material. Subsequent fusion gene analysis and/or use of specific immunohistochemical surrogate markers can be used to substantiate the diagnosis.