Ewing Sarcoma Research Articles

Panobinostat Synergizes with Chemotherapeutic Agents and Improves Efficacy of Standard-of-Care Chemotherapy Combinations in Ewing Sarcoma Cells.

Background: The survival rate of patients with Ewing sarcoma (EWS) has seen very little improvement over the past several decades and remains dismal for those with recurrent or metastatic disease. HDAC2, ALK, JAK1, and CDK4 were identified as potential targets using RNA sequencing performed on EWS patient tumors with the bioinformatic analysis of gene expression. Methods/Results: The pan-HDAC inhibitor Panobinostat was cytotoxic to all the Ewing sarcoma cell lines tested. Mechanistically, Panobinostat decreases the expression of proteins involved in the cell cycle, including Cyclin D1 and phospho-Rb, and DNA damage repair, including CHK1. Further, Panobinostat induces a G1 cell cycle arrest. The combination of Panobinostat with Doxorubicin or Etoposide, both of which are used as standard of care in upfront treatment, leads to a synergistic effect in EWS cells. The combination of Panobinostat and Doxorubicin induces an accumulation of DNA damage, a decrease in the expression of DNA damage repair proteins CHK1 and CHK2, and an increase in caspase 3 cleavage. The addition of Panobinostat to standard-of-care chemotherapy combinations significantly reduces cell viability compared to that of chemotherapy alone. Conclusions: Overall, our data indicate that HDAC2 is overexpressed in many EWS tumor samples and HDAC inhibition is effective in targeting EWS cells, alone and in combination with standard-of-care chemotherapy agents. This work suggests that the addition of an HDAC inhibitor to upfront treatment may improve response.

Geranylgeranyl diphosphate synthase inhibition impairs osteoclast differentiation, morphology and resorptive activity

Abstract Nitrogen bisphosphonates (NBPs), such as zoledronic acid, target the enzyme farnesyl diphosphate synthase (FDPS) in the isoprenoid biosynthetic pathway (IBP), and are the frontline treatment for osteolytic bone diseases. The strong affinity of these agents for bone limits their distribution out of the skeleton. Geranylgeranyl diphosphate synthase (GGDPS) is directly downstream to FDPS in the IBP and novel GGDPS inhibitors such as RAM2061 have been shown to have key drug-like features including prolonged half-life, metabolic stability, and systemic distribution. Furthermore, RAM2061 exerts anti-neoplastic benefits in mouse models of multiple myeloma and Ewing sarcoma. Therefore, we are interested in determining the potential impact of RAM2061 on osteoclast biology and bone remodeling. Studies utilizing undifferentiated RAW264.7 cells demonstrated that treatment with RAM2061 depletes cells of GGPP, impairs protein geranylgeranylation and induces markers of the unfolded protein response pathway and apoptosis. Differentiation of RAW264.7 cells to mature osteoclasts is disrupted by RAM2061, resulting in decreased numbers of mature osteoclasts, altered morphology and decreased tartrate resistant acid phosphatase activity. Treatment of fully differentiated RAW264.7 cells with RAM2061 led to decreased resorptive activity. Confocal microscopy studies revealed that RAM2061 disrupts Cdc42 localization, inhibiting proper actin ring formation in osteoclasts. No significant impact on bone turnover markers or bone histomorphology was observed following a 3-week treatment of CD-1 mice with RAM2061, although decreased numbers of osteoclasts were observed. Liquid chromatography–tandem mass spectrometry studies confirmed accumulation of RAM2061 in bone from the in vivo studies as well as hydroxyapatite binding in vitro. In conclusion, these studies are the first to demonstrate the anti-osteoclastic activity of GGDPS inhibitor treatment and support future studies exploring the therapeutic benefit of this novel therapy in the setting of pathological bone remodeling.

Advancing Anticancer Drug Discovery: Leveraging Metabolomics and Machine Learning for Mode of Action Prediction by Pattern Recognition.

A bottleneck in the development of new anti-cancer drugs is the recognition of their mode of action (MoA). Metabolomics combined with machine learning allowed to predict MoAs of novel anti-proliferative drug candidates, focusing on human prostate cancer cells (PC-3). As proof of concept, 38 drugs are studied with known effects on 16 key processes of cancer metabolism, profiling low molecular weight intermediates of the central carbon and cellular energy metabolism (CCEM) by LC-MS/MS. These metabolic patterns unveiled distinct MoAs, enabling accurate MoA predictions for novel agents by machine learning. The transferability of MoA predictions based on PC-3 cell treatments is validated with two other cancer cell models, i.e., breast cancer and Ewing's sarcoma, and show that correct MoA predictions for alternative cancer cells are possible, but still at some expense of prediction quality. Furthermore, metabolic profiles of treated cells yield insights into intracellular processes, exemplified for drugs inducing different types of mitochondrial dysfunction. Specifically, it is predicted that pentacyclic triterpenes inhibit oxidative phosphorylation and affect phospholipid biosynthesis, as confirmed by respiration parameters, lipidomics, and molecular docking. Using biochemical insights from individual drug treatments, this approach offers new opportunities, including the optimization of combinatorial drug applications.

ANGIOGENIC FACTORS AS PREDICTORS OF SURVIVAL IN PATIENTS WITH BONE SARCOMAS

Introduction. Primary bone sarcomas are relatively rare neoplasms. They occur predominantly in adolescents and young adults, are characterized by an aggressive clinical course and a high metastatic potential, have a poor prognosis. In this regard, the problem of stratifying the risk of metastasis and death in order to select the optimal treatment tactics always remains relevant. The study of such markers as endostatin, vascular endothelial growth factor (VEGF), insulin-like growth factors IGF-1, IGF-2 as potentially informative predictors of survival in patients with bone sarcomas is pathogenetically determined by their involvement in the processes of tumor growth and metastasis. Aim – to analyze the relationship between pre-treatment serum levels of endostatin, VEGF, IGF-1 and IGF-2 with overall survival rates in patients with bone sarcomas. Material and methods. An analysis of overall survival rates was carried out in 134 patients with malignant bone tumors aged from 1 to 73 years (Me=27.0 years; Q1–Q3: 18.0 – 43.0 years), among them 87 men (64.9%) and 47 women (35.1%). All patients comprised 4 groups: osteosarcoma (n=58), undifferentiated pleomorphic sarcoma (n=5), Ewing sarcoma (n=29), chondrosarcoma (n=42). In all of them, before the start of specific antitumor treatment, the levels of endostatin, VEGF, IGF-1, and IGF-2 in the blood serum were determined using enzyme immunoassay. The follow-up period ranged from 1 to 229 months (Me=23.0 months; Q1–Q3: 10.0–121.0 months). To analyze overall survival, life tables and Kaplan–Meier curves were constructed. The effect of the studied serum markers on survival rates was assessed using the logrank test and Cox proportional hazards regression model. Results. During observation, death occurred in 51 patients (38.1%). In the group of deceased patients, serum levels of endostatin and IGF-2 were statistically significantly increased compared to the group of surviving patients (p 0.001 and p=0.011, respectively). Kaplan-Meier survival analysis using the logrank test revealed statistically significant differences in overall survival between the four groups of patients with different serum levels of endostatin, IGF-1 and IGF-2. The Cox regression method established the prognostic significance of endostatin as a predictor of overall survival (HR=1.012; p=0.013). Conclusion. Endostatin, IGF-1, IGF-2 can serve as predictors of overall survival of patients with bone sarcomas.

Risk-Stratified Radiotherapy in Pediatric Cancer

While the cure rate of cancer in children has markedly improved in the last few decades, late effects continue to be a problem in survivors. Radiotherapy, which is a major component of treatment in many cancers, is one of the major agents responsible for late toxicity. In the past decade, radiotherapy has been omitted in patients achieving excellent response to chemotherapy, such as in Hodgkin lymphoma and some Wilms tumors with lung metastases. Likewise, response to chemotherapy has been used to determine whether lower doses of radiation can be delivered in intracranial germinoma and pediatric nasopharyngeal carcinoma. Molecular subtyping in medulloblastoma is currently being employed, and in WNT-pathway M0 tumors, the reduction in radiotherapy dose to the craniospinal axis and tumor bed is currently being investigated. Finally, dose escalation was recently evaluated in patients with rhabdomyosarcoma > 5 cm who do not achieve a complete response to initial 9 weeks of chemotherapy as well as for unresectable Ewing sarcoma patients to improve local control.

Outcome of Ewing sarcoma in children: Twenty years experience from a single center

ABSTRACT Objective: Ewing sarcoma (ES) is a significant malignancy in pediatric patients, with a notable impact on bone health. Despite advances in treatment, ES still poses challenges, particularly in cases of metastasis or relapse. This study aims to evaluate the outcomes of ES in children treated at our center over a twenty-year period. Patients and Methods: We retrospectively reviewed pediatric patients diagnosed with ES at our center between January 2004 and February 2024. Data including demographic information, tumor characteristics, treatment modalities, and survival outcomes were analyzed. Results: Among 986 pediatric solid tumor cases, 137 (13.8%) were diagnosed with ES. After excluding ineligible cases, 115 ES cases were included in the study. The most common sites of involvement were the lower extremities. Metastatic disease was observed in 35.8% of cases, with the lungs being the most common site. Advanced age, and pelvic involvement were associated with poor prognosis. Histopathological response to neoadjuvant chemotherapy, represented by tumor necrosis rate, metastatic and relapse disease significantly influenced survival outcomes. Conclusion: Despite multimodal therapies, ES in children, especially with metastatic disease or relapse, presents a challenging prognosis. Early diagnosis and the development of novel treatment strategies are imperative to improve outcomes for these patients.

A Review of Published Cases Regarding the Amphotericin B Deoxycholate Overdose in the Pediatric Population and a Case Report.

Considering the fact that two available and commonly used formulations of amphotericin B could be used instead of each other by mistake. Also, an updated and comprehensive data regarding management of this medication error was not available; the current review was conducted to gather available data among the pediatric population and discuss management and outcome of patients in case such an error occurs. We review all the cases of amphotericin B overdose which reported in PubMed and google scholar so far then discuss an 8-years-old girl diagnosed with Ewing sarcoma who inadvertently received five times more than therapeutic dose of amphotericin B deoxycholate (5mg/kg/day).In total, ten of the cases were exactly matched to our purpose of the study. In our case, fluid and electrolyte management was aggressively undertaken and she was put under cardiac monitoring for 7 days following detection of the medication error. Finally, she was discharged from hospital with stable condition. Reviewed data in this manuscript showed that amphotericin B deoxycholate overdose could cause severe complications and lead to cardio toxicity, electrolyte imbalance and death. Aggressive cardiac, fluid and electrolyte monitoring and management of any problem as soon as they were detected was the pathway followed by the authors of this review and others who faced this medication error. The role of NAC and hydrocortisone in the managing amphotericin B deoxycholate overdose requires further investigation.

Evaluating Circulating Biomarkers for Diagnosis, Prognosis, and Tumor Monitoring in Pediatric Sarcomas: Recent Advances and Future Directions.

Pediatric sarcomas present a significant challenge in oncology. There is an urgent need for improved therapeutic strategies for high-risk patients and better management of long-term side effects for those who survive the disease. Liquid biopsy is emerging as a promising tool to optimize treatment in these patients by offering non-invasive, repeatable assessments of disease status. Circulating biomarkers can provide valuable insights into tumor genetics and treatment response, potentially facilitating early diagnosis and dynamic disease monitoring. This review examines the potential of liquid biopsies, focusing on circulating biomarkers in the most common pediatric sarcomas, i.e., osteosarcoma, Ewing sarcoma, and rhabdomyosarcoma. We also highlight the current research efforts and the necessary advancements required before these technologies can be widely adopted in clinical practice.

Assessment of a Structurally Modified Alternanthera Mosaic Plant Virus as a Delivery System for Sarcoma Cells

The virions of plant viruses and their structurally modified particles (SP) represent valuable platforms for recombinant vaccine epitopes and antitumor agents. The possibility of modifying their surface with biological compounds makes them a tool for developing medical biotechnology applications. Here, we applied a new type of SP derived from virions and virus-like particles (VLP) of Alternanthera mosaic virus (AltMV) and well-studied SP from Tobacco mosaic virus (TMV). We have tested the ability of SP from AltMV (AltMV SPV) and TMV virions also as AltMV VLP to bind to and penetrate Ewing sarcoma cells. The adsorption properties of AltMV SPV and TMV SP are greater than those of the SP from AltMV VLP. Compared to normal cells, AltMV SPV adsorbed more effectively on patient-derived sarcoma cells, whereas TMV SP were more effective on the established sarcoma cells. The AltMV SPV and TMV SP were captured by all sarcoma cell lines. In the established Ewing sarcoma cell line, the effectiveness of AltMV SPV penetration was greater than that of TMV SP. The usage of structurally modified plant virus particles as a platform for drugs and delivery systems has significant potential in the development of anticancer agents.

Primary Mast Cell Sarcoma of the Maxillary Sinus and Gingiva Mimicking Malignant Neuroendocrine Tumor: A Case Report

Mast cell sarcoma (MCS) is an extremely rare and aggressive malignancy primarily affecting bones, with limited literature associating it with neuroendocrine marker expression. This report presents a rare case of MCS arising in the maxillary sinus and gingiva. A 74-year-old man presented with a progressively enlarging ulcer on the right-sided upper gingiva. Magnetic resonance imaging revealed a 3.4 cm tumor on the floor of the right maxillary sinus. The patient underwent an inferior maxillectomy and right-sided neck dissection. Microscopically, the tumor consisted of monotonous round cells with oval nuclei, vesicular chromatin, inconspicuous nucleoli, and brisk mitoses. A panel of immunohistochemical stains was initially applied to exclude common sinonasal undifferentiated neoplasms, such as sinonasal undifferentiated carcinoma, melanoma, rhabdomyosarcoma, Ewing sarcoma, and lymphoma. The tumor cells showed patchy staining for INSM1 and synaptophysin, but were negative for AE1/AE3, CAM5.2, p40, chromogranin, S100, HMB45, NKX2.2, desmin, CD45 (LCA), CD3, and CD20, with intact INI1 and BRG1 expression. No specific diagnosis could be rendered based on the staining results, leading to consideration of other rare malignancies. Additional staining revealed positivity for CD117, mast cell tryptase, CD13, CD33, CD43, and CD68, confirming the MCS diagnosis. Molecular testing for KIT mutation was negative. Subsequent bone marrow biopsy demonstrated infiltration of atypical mast cells, which led to a diagnosis of mast cell leukemia. Despite high-dose chemotherapy, the patient died three months after the initial diagnosis. The undifferentiated epithelioid morphology and unusual aberrant neuroendocrine marker expression posed significant diagnostic challenges. The major differential diagnoses were discussed in this report.

Contemporary surgical management of osteosarcoma and Ewing sarcoma.

The incidence of malignant bone tumors has remained relatively stable over the past two decades between 8% and 9% per 1,000,000 in North America. Multidisciplinary treatment is paramount for optimal care combining surgical resection, chemotherapy, and rehabilitation. Surgical treatment aims for a negative margin resection of the sarcoma with a personalized reconstruction plan. Limb salvage surgery (LSS) is possible in the majority of cases; however, amputation (including rotationplasty) may be required or preferred. Reconstruction can be achieved utilizing endoprostheses, allograft, autograft, or a combination of these techniques. Emerging technologies such as 3D printing of implants and cutting guides, and intraoperative navigation have helped to improve options for LSS.

Malignant Rhabdoid Tumor masquerading as Neuroblastoma: A rare Case-report

Abstract Introduction/Objective Malignant rhabdoid tumors (MRT) predominantly impact infants and young children, typically occurring around the age of 15 months. While they can emerge from soft tissues throughout the body, but commonly initiate in the kidneys. Neuroblastoma-like characteristics are seldom observed within the varied phenotypes of malignant rhabdoid tumors. Here, we present an exceptionally rare and distinctive subtype of malignant rhabdoid tumor exhibiting features akin to neuroblastoma localized within the unusal parapharyngeal space. Methods/Case Report A 2-month-old female presented to the ED with an enlarging right cervical neck mass. The mother reported a one-week history of upper respiratory tract symptoms and noticed an enlarging mass of her right neck. CT reported a “parapharyngeal abscess with airway compression”. The patient was started on Augmentin with no significant improvement. Repeat CT with contrast demonstrated an enlarging rim-enhancing 3 cm mass involving the right parapharyngeal space, trachea, and right carotid arteries. Laryngoscopy and incisional biopsy of right neck lymph nodes demonstrated a high-grade malignancy with prominent nucleoli, high N/C ratio and scant cytoplasm. The tumor tested positive for CD 99, synaptophysin, and neurofilament, leading to the initial diagnosis of neuroblastoma. However, molecular analysis uncovered the loss of INI-1 on 22q11.2, prompting a reevaluation and a final diagnosis of MRT with neuroblastoma-like characteristics was made. Results (if a Case Study enter NA) NA Conclusion A range of tumors displaying distinct “rhabdoid” cytological features are collectively termed as malignant rhabdoid tumors (MRTs). Conventional immunohistochemistry (IHC) staining for CD99, synaptophysin, neurofilament, and myogenin might suggest neuroblastoma, Ewing sarcoma, or rhabdomyosarcoma. However, the absence of INI-1 expression provides a definitive diagnosis. INI-1 loss, a purported tumor suppressor gene located on chromosome 22q11.2, solidifies the tumor’s classification as malignant rhabdoid tumor (MRT). Additionally, a positive neurofilament stain in MRT is crucial for diagnostic and therapeutic assessments. This differentiation is vital, given the dismal prognosis of MRT with a 5-year survival rate of less than 10%.

High dose chemotherapy with autologous stem cell rescue in children and young adults with high-risk Ewing sarcoma: A single institute experience in Taiwan.

A combination treatment of surgery, chemotherapy, and radiotherapy can improve the survivals of pediatric patients with Ewing sarcoma (ES). However, prognosis remains poor for patients with metastatic disease at diagnosis or recurrence. Other high-risk (HR) features include large tumor burden, tumors of the axial skeleton and poor histologic response. Several studies have documented high dose chemotherapy with autologous stem cell rescue (HDC-ASCR) to be effective in such patients. In this retrospective study, we present the results of HDC-ASCR for high-risk Ewing sarcoma in children and young adults in a single institute. From March 2004 to March 2021, patients with ES, Ewing-like sarcoma, or round cell sarcoma received HDC-ASCR as part of treatment were included. The patients' characteristics, disease status, stem cell dose, engraftment status, post-transplant complications, and outcomes were analyzed. Twenty patients receiving HDC-ASCR at complete response (n = 6), partial response (n = 13), and stable disease (n = 1) were enrolled. The male to female ratio was 11:9. Median age at diagnosis and transplant was 15.6 years old (range: 3.3-28.9) and 16.2 (range: 4.2-29.9), respectively. The conditioning regimens included ifosfamide-based in two and melphalan-based in 19. All patients achieved successful engraftment without tansplant-related mortality. The 5-year progression-free and overall survival (OS) rate were 35% and 54.5%, respectively. The causes of death (n = 8) were all contributed to disease progression. Patients in the complete response group or with localized HRES exhibited a higher 5-year OS (p = 0.047 and 0.05, respectively). Compared to the historical cohort without HDC-ASCR as part of primary treatment, the current cohort had a significantly better 5-year OS (p = 0.018). HDC-ASCR seems promising as an alternative treatment for HRES in improving OS in this retrospective study with limited case number.

Pneumocystis jirovecii pneumonia in hemato-oncological patients; 10 years of experience at Hospital Infantil Teletón de Oncología

Abstract Background Pneumocystis jirovecii pneumonia is an opportunistic infection that most frequently affects immunocompromised people, especially patients with HIV; clinical presentation is nonspecific and mortality rate in patients without HIV ranges are between 30% and 75%. In the international literature, there are few case reports of pediatric oncology patients. A series of cases is presented with the objective of describing the epidemiological characteristics, clinical presentation, treatment, and outcomes of Pneumocystis jirovecii pneumonia in this population group. Methods An observational, descriptive, and retrospective study was carried out in cancer patients under 18 years, with clinically compatible symptoms, an imaging study suggestive of the pneumonia, and identification of P. jirovecii using a PCR test of bronchial aspirate at Hospital Infantil Teletón de Oncología in Querétaro Mexico, since November 2014 to June 2023. Results A total of 17 events were reported with a median age of 9.8 years, 14/17 (82%) with a diagnosis of acute leukemias, 1/17 (6%) Ewing sarcoma, 1/17 (6%) lymphoma large cell anaplastic and 1/17 (6%) neuroblastoma. Regarding their therapeutic phases, 7/17 (41%) were in consolidation, 4/17 (23%) induction, 3/17 (18%) allogeneic HSCT (Hematopoietic stem-cell transplantation), 2/17 (12%) in surveillance, and 1/17 (6%) in maintenance. The clinical presentation in our patients was characterized by the presence of fever in 15/17 (88%), dry cough in 10/17 (59%) and 17/17 (100%) developed acute respiratory distress syndrome, which was classified as mild in 7/17 (41%), moderate in 5/17 (29%) and severe in 5/17 (29%). 13/17 (75%) presented distributive shock. All our patients underwent chest x-rays, 12/17 (70.5%) presented bilateral interstitial infiltrate, 4/17 (23.5%) consolidation, and 1/17 (6%) pleural effusion. Lung CT (computed tomography) was performed in 4/17 (23.5%), and 4/4 (100%) presented ground glass opacities. All of our patients were admitted to the PICU (Pediatric intensive care unit) and 16/17 (94%) required invasive mechanical ventilation. All receive treatment with TMP-SMX (Trimethoprim-sulfamethoxazole). 4/17 patients died (23%) of whom none received prophylaxis. 3/17 patients (18%) received prophylaxis with trimethoprim-sulfamethoxazole (TMP-SMX). Conclusion The present study is the first study in Mexico that compiles cases of Pneumocystis Jirovecii pneumonia in pediatric oncology patients. P. jirovecii pneumonia remains a rare cause, but represents a potentially fatal cause in oncology patients, so it is important to have a high clinical suspicion during the evaluation of an immunocompromised patient with evidence of pneumonia during all treatment phases with chemotherapy, in order to start treatment promptly. Thus, we also emphasize the importance of adequate prophylaxis as the most important preventive measure.

Treatment of malignant primary cardiac tumors requires attention to cardiovascular complications: a single-center, retrospective study.

Malignant primary cardiac tumors require multimodal approaches including surgery, chemotherapy and radiotherapy, but these treatments can be associated with cardiovascular complications. However, few reports have described the cardiovascular complications related to primary cardiac tumor treatment because of their rarity. Clinical records of patients with primary cardiac tumors treated at Kyushu University Hospital from January 2010 to August 2021 were retrospectively examined. Of the 47 primary cardiac tumor patients, 13 (28%) were diagnosed with malignancy, including 5 angiosarcomas, 3 intimal sarcomas, 3 diffuse large B-cell lymphomas, 1 Ewing's sarcoma and 1 fibrosarcoma. Cardiovascular events were observed in 10 patients (77%), including cardiac dysfunction in 6 patients, arrhythmias in 5 patients, right heart failure in 2 patients, and excessively prolonged prothrombin time due to the combination of warfarin and chemotherapy in 1 patient. Two patients who showed notable cardiac complications are described. Case A involved a 69-year-old woman who underwent surgery for a left atrial intimal sarcoma, followed by postoperative chemotherapy with doxorubicin plus ifosfamide and radiotherapy. After three cycles of chemotherapy and sequential radiotherapy, her left ventricular ejection fraction decreased to 34%, and ongoing heart failure therapy was required. Case B involved a 66-year-old man who received chemotherapy for primary cardiac lymphoma, resulting in tumor shrinkage. However, due to tumor involvement of the intraventricular septum, atrioventricular block developed, requiring cardiac pacemaker implantation. High incidences of cardiac failure and arrhythmias were observed during multimodal treatments for malignant primary cardiac tumors. Proper management of complications may lead to a favorable prognosis in patients with malignant primary cardiac tumors.

Nuclear DUX4 immunohistochemistry is a highly sensitive and specific marker for the presence of CIC::DUX4 fusion in CIC-rearranged sarcomas: a study of 48 molecularly confirmed cases.

CIC-rearranged sarcomas (CRS) are clinically aggressive undifferentiated round cell sarcomas (URCS), commonly driven by CIC::DUX4. Due to the repetitive nature of DUX4 and the variability of the fusion breakpoints, CIC::DUX4 fusion may be missed by molecular testing. Immunohistochemical (IHC) stains have been studied as surrogates for the CIC::DUX4 fusion. We aim to assess the performance of DUX4 IHC in the work-up of CRS and its expression in non-CRS round cell or epithelioid neoplasms. Cases of molecularly confirmed CRS (n = 48) and non-CRS (n = 105) were included. CRS cases consisted of 35 females and 13 males, with ages ranging from less than 1 year to 67 years (median = 41 years). Among the molecularly confirmed non-CRS cases, C-terminal DUX4 expression was investigated in Ewing sarcomas (38 cases), alveolar rhabdomyosarcomas (18 cases), desmoplastic smallround cell tumours (12 cases) and synovial sarcomas (n = five), as well as in non-mesenchymal neoplasms such as SMARCA4/SMARCB1-deficient tumours (n = five), carcinomas of unknown primary (n = three) and haematolymphoid neoplasms (four cases). DUX4 IHC was considered positive when strong nuclear expression was detected in more than 50% of neoplastic cells. When used as a surrogate for the diagnosis of CRS, the sensitivity and specificity of DUX4 IHC was 98 and 100%, respectively. Only one CRS case was negative for DUX4 IHC and harboured a CIC::FOXO4 fusion. DUX4 IHC is a highly sensitive and specific surrogate marker for the presence of CIC::DUX4 fusion, demonstrating its utility in establishing a diagnosis of CRS.

Role of 18F-FDG-PET/CT in the initial staging of very high-risk Ewing Sarcoma in a prospective multicentric Phase II Study: Is there still a place for bone marrow sampling?

The Ewing Sarcoma Family of Tumors (ESFT) constitutes a group of rare malignancies, wherein approximately one-third of cases exhibit metastatic spread, particularly impacting prognosis when bone and/or bone marrow (BM) are involved. Primary extra-pulmonary metastatic ESFT often necessitates intensified therapeutic approaches. Accurate staging plays a pivotal role in clinical decision-making, with fluorine-18-fluorodeoxyglucose-positron emission tomography/computed tomography (PET/CT) currently serving as a non-invasive modality for assessing ESFT's BM extent. In the French phase II COMBINAIR3 (NCT03011528) study, a comprehensive approach for patients with extra-pulmonary ESFT metastasis was evaluated. We prospectively compared the efficacy of PET/CT to BM aspiration and biopsy (BMAB) analysis in patients undergoing initial staging. Among the 42 patients analyzed (median age 14 y, 2:1 male/female ratio), 45% presented with pelvic primary tumors and 83% had bone/BM involvement at diagnosis. Our findings showed PET/CT had 100% specificity and 83.3% sensitivity in detecting initial BM involvement. Overall, PET/CT correctly classified 92.8% of patients, reaching 100% accuracy in patients identified with bone involvement, thus surpassing the standard BMAB. These results suggest that the conventional use of BMAB in the initial staging of high-risk ESFT patients can be omitted, promoting PET/CT as a non-invasive alternative, thus improving staging accuracy and treatment decisions in ESFT management.

Pharmacological targeting of P300/CBP reveals EWS::FLI1-mediated senescence evasion in Ewing sarcoma

Ewing sarcoma (ES) poses a significant therapeutic challenge due to the difficulty in targeting its main oncodriver, EWS::FLI1. We show that pharmacological targeting of the EWS::FLI1 transcriptional complex via inhibition of P300/CBP drives a global transcriptional outcome similar to direct knockdown of EWS::FLI1, and furthermore yields prognostic risk factors for ES patient outcome. We find that EWS::FLI1 upregulates LMNB1 via repetitive GGAA motif recognition and acetylation codes in ES cells and EWS::FLI1-permissive mesenchymal stem cells, which when reversed by P300 inhibition leads to senescence of ES cells. P300-inhibited senescent ES cells can then be eliminated by senolytics targeting the PI3K signaling pathway. The vulnerability of ES cells to this combination therapy suggests an appealing synergistic strategy for future therapeutic exploration.

Case report and literature review: A young man with giant intra-abdominal Ewing sarcoma.

Extraosseous Ewing sarcoma (EES) is a rare manifestation within the Ewing sarcoma tumor family (ESFT). Its clinical manifestations lack specificity, intestinal obstruction is the main symptom but can also present with abdominal pain, gastrointestinal bleeding, and other discomforts, making it prone to misdiagnosis as intestinal mesenchymal tumor. A 29-year-old male was admitted to the hospital with intestinal obstruction symptoms and abdominal CT suggesting "left abdominal occupation." The patient was initially misdiagnosed as intestinal mesenchymal tumor, and was later definitively diagnosed as abdominal Ewing sarcoma by postoperative pathology and genetic testing. Due to the patient's surgical indication, surgical resection with exploratory laparotomy was performed and then the patient underwent systemic chemotherapy. Intraoperatively, we found a 15-cm tumor originating from the proximal jejunum, with invasion into the peritoneum, duodenum, jejunum, and colon. Finally, the pathological report revealed Ewing sarcoma. Giant abdominal Ewing sarcoma with a diameter of 15 cm is rare. Considering postoperative pathology and genetic testing, abdominal Ewing sarcoma was suspected. The patient was successfully treated using surgery.

Impaired neutrophil-mediated cell death drives Ewing's Sarcoma in the background of Down syndrome.

Ewing Sarcoma (EWS) has been reported in seven children with Down syndrome (DS). To date, a detailed assessment of this solid tumour in DS patients is yet to be made. Here, we characterise a chemo-resistant mediastinal EWS in a 2-year-old DS child, the youngest ever reported case, by exploiting sequencing approaches. The tumour showed a neuroectodermal development driven by the EWSR1-FLI1 fusion. The inherited myeloperoxidase deficiency of the patient caused failure of neutrophil-mediated cell death and promoted genomic instability. In this context, the tumour underwent genome-wide near haploidisation resulting in a massive overexpression of pro-inflammatory cytokines. Recruitment of defective neutrophils fostered rapid evolution of this EWS.