Primary Ewing's Sarcoma of the Sternum in an Adult Male: A Rare Case Report.

Ewing's sarcoma, a rare primary bone malignancy primarily affecting adolescents and young adults, typically manifests in the pelvic bones and femur. Primary Ewing's sarcoma of the sternum is exceptionally rare, constituting less than 1% of cases. We present a case of a 34-year-old man with a 2-month history of anterior chest wall pain initially attributed to muscular spasm. Subsequently, the patient developed a palpable mass and imaging demonstrated a mid-lower sternal lesion with cortical destruction and soft tissue involvement, confirmed as Ewing's sarcoma on biopsy. In addition, a suspicious lesion was identified in the left distal tibia, which was histologically confirmed as a metastasis from the primary sternal sarcoma. Neoadjuvant chemotherapy preceded partial sternotomy with rib resection and reconstruction, achieving clear surgical margins. Postoperative evaluation showed shrinkage in the sternal lesion and near-resolution of the tibial metastasis. Subsequent chemotherapy cycles resulted in no evidence of the disease on the follow-up positron emission tomography scan. This case underscores the diagnostic challenges of primary sternal Ewing's sarcoma and emphasizes the importance of early recognition and comprehensive evaluation in managing such rare presentations.

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.

Establishment and characterization of a patient-derived metastatic extraskeletal Ewing sarcoma cell line ES-ZSS-1.

The methods available for treating metastatic Ewing sarcoma (ES) are inadequate; thus, innovative therapeutic approaches need to be developed. However, the lack of clinically relevant ES models has hindered the discovery of drugs for this disease. In this study, we established and characterized a patient-derived xenograft (PDX) cell line model, which was constructed using tumor tissue from a patient with metastatic extraskeletal ES. The cells were found to recapitulate the morphological and histopathological features of the patient tumor and were designated as ES-ZSS-1. The cells harbor the characteristic EWSR1-FLI1 infusion and underwent successive passages in vitro. By performing gene expression profiling, we found that the mutation in STAG2 was the most frequent. An increase in Twist1 and epithelial-to-mesenchymal transition (EMT) was recorded. These genetic features might be relevant to metastasis and resistance to chemotherapy. To summarize, the novel patient-derived ES cell line we developed closely mimics the phenotype and genotype of patient tumors, making it a reliable tool for research on metastatic ES.

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

RATIONALE: 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. PATIENT CONCERNS: A 29-year-old male was admitted to the hospital with intestinal obstruction symptoms and abdominal CT suggesting "left abdominal occupation." DIAGNOSIS: The patient was initially misdiagnosed as intestinal mesenchymal tumor, and was later definitively diagnosed as abdominal Ewing sarcoma by postoperative pathology and genetic testing. INTERVENTIONS: Due to the patient's surgical indication, surgical resection with exploratory laparotomy was performed and then the patient underwent systemic chemotherapy. OUTCOMES: 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. LESSONS: 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.

Knockdown of PRDX2 Inhibits the Proliferation, Growth, Migration, Invasion, and MMP9 Activity of Ewing's Sarcoma Cells Cultured In Vitro.

BACKGROUND: Ewing's sarcoma (ES) is the second most common malignant primary bone tumor in children and adolescents. Peroxiredoxin 2 (PRDX2) is an antioxidant enzyme. AIMS: Here, we investigated the role and mechanism of PRDX2 in the development of ES. METHODS AND RESULTS: PRDX2 expression was knocked down in A673 and RDES cells by specific siRNA interference (si-PRDX2). Knockdown of PRDX2 strongly inhibited the proliferation, growth, migration, invasion, and MMP9 activity and induces apoptosis of A673 and RDES cells. si-PRDX2 significantly inhibited the phosphorylation of Akt and the expression of cyclin D1. The transcription factor that might regulate PRDX2 transcription was predicted with the JASPAR and UCSC databases, and analyzed using dual-luciferase and Chromatin co-immunoprecipitation experiments. SNAI1 could activate the transcription of PRDX2 by binding to predicted promoter binding site. CONCLUSION: PRDX2 may be a potential therapeutic target for ES.

Clinicopathological characteristics and genetic features of young and senior Ewing sarcoma patients.

BACKGROUND: Ewing sarcoma (EwS) is a highly malignant and heterogeneous tumor. Exploring clinicopathological characteristics and genetic features of EwS is critical for prognosis and treatment regimen. METHODS: Clinicopathological characteristics and genetic features of young (≤ 30y) and senior (> 30y) EwS patients were analyzed based on histology, phenotype, and next-generation sequencing (NGS) detection. RESULTS: The young group (18/36) presented nontypical EwS histological morphology, whereas the senior group (18/36) presented typical morphology. The prognosis of the young group was found to be worse compared with the senior group for patients without metastasis at the initial diagnosis. DNA- and RNA-based NGS was conducted on 20 extraosseous EwS patients. 16/20 samples demonstrated EWSR1-FLI1 fusion and 4/20 demonstrated EWSR1-ERG fusion. However, 13/16 EWSR1-FLI1fusions were detected both in DNA- and RNA-based NGS, 1/16 was detected only at the DNA level, and 2/16 were detected only at the RNA level. An analysis of the genetic profiles of the EWSR1-FLI1 cases revealed that the young group was inclined to couple with more copy number variations (CNV), such as CCND1, CDK4 amplification, and fusion variations, such as CHEK1-EWSR1, SLIT2-EWSR1, and EWSR1-FAM76B fusion. The senior group was more likely to have SNV or Indel mutations, such as EPHA3 and STAG2 mutations. Moreover, patients with more CNV abnormalities had a worse prognosis than those with predominantly SNP variants. In addition, compared with the senior group, the young group had significantly higher CyclinD1 protein expression. CONCLUSION: Clinicopathological characteristics and genetic features in young and senior EwS patients differed significantly. Targeting cell cycle dysregulation based on age subgroup may be a potential therapeutic strategy for Ewing sarcoma.

Lung and bone metastases patterns in Ewing sarcoma: Chemotherapy improves overall survival.

Ewing sarcoma (ES) is a small round cell malignancy, mainly in the bone tissue, followed by the soft tissue. Lung metastases (LM) and bone metastases (BM) are the most common types of metastases. From 2010 to 2018, the Surveillance, Epidemiology, and End Results database diagnosed 242 cases of ES with LM, 186 cases of ES with BM, and 74 cases of ES with LM and BM. Univariate and multivariate logistic regression analyses were used to determine the risk factors for LM and/or BM, and Kaplan-Meier curves and Cox regression analysis were used to determine the prognostic factors for LM and/or BM. Tumor size ≥50 mm, N1 stage, BM, liver metastases, and surgical treatment were significantly correlated with LM; tumor size >100 mm, brain metastases, LM, surgical treatment, and chemotherapy were significantly correlated with BM; female, N1 stage, brain metastases, liver metastases, and surgical treatment were significantly correlated with LM and BM. Older age, BM, higher T stage, no surgical treatment, and no chemotherapy were harmful to the survival of ES patients with LM; older age, female, LM, and no chemotherapy were harmful to the survival of ES patients with BM; older age and no chemotherapy were harmful to the survival of ES patients with LM and BM. Larger tumor size, N1 stages, and organ metastases were significantly associated with ES patients with LM and/or BM. Chemotherapy is effective in improving the survival.

Let it glow: Intraoperative visualization of pulmonary metastases using pafolacianine, a next-generation fluorescent agent, for young adults undergoing pulmonary metastasectomy.

A new generation of disease-specific molecular imaging agents is poised to revolutionize fluorescence-guided surgery. Pafolacianine has been approved for adult lung and ovarian cancers. We demonstrate a proof of concept for pediatric surgeons treating young adults with pulmonary metastatic sarcomas. Five successful fluorescence-guided pulmonary metastasectomy operations were performed in young adult patients with metastatic osteosarcoma or Ewing sarcoma following administration of pafolacianine. All osteosarcoma lesions identified using standard techniques were also markedly fluorescent in patients. Novel fluorescent molecular agents targeted to tumor-specific receptors have promise of increased sensitivity and specificity for detecting metastatic nodules and enhancing surgical clearance of disease.

Ewing sarcoma among children 5 years of age or younger: Is it a different disease?

INTRODUCTION: Children ≤5 years of age with Ewing's sarcoma (ES) possibly have a distinct disease biology, data on which are scarce. We evaluated clinical features, outcomes, and prognostic factors of ES among children with age ≤5 years. METHODS: Children with ES registered between 2003 and 2019 were included. Baseline clinical and treatment details were retrieved from medical records. Prognostic factors were identified using multivariable Cox regression. Clinical features and outcomes of children ≤5 years were compared with those greater than 5 years by chi-square and log-rank tests. Propensity score-matched (PSM) analysis was done to evaluate the impact of age on survival in the metastatic and localized subgroups. RESULTS: Out of the 859 patients, 86 (10%) were ≤5 years of age (median age 4 years, 60 males [69.8%]). The most common location was the extremities (37.2%), followed by thorax (27.9%) and head and neck (H&N) (22.1%); baseline metastases were seen in 25 patients (29.8%). The median event-free-survival (EFS) and overall survival (OS) were 25.6 and 68.7 months, respectively. Metastatic disease predicted inferior OS (hazard ratio [HR] = 2.54, p = .018) and EFS (HR = 2.47, p = .007], symptom duration ≤3 months predicted an inferior OS (HR = 2.17, p = .048). Compared to age greater than 5 years, younger children had more H&N and less pelvic primaries (p < .001) and lesser baseline metastases (p = .037). PSM analysis did not reveal any significant impact of age on OS in the metastatic (HR = 1.59, p = .29) or localized cohort (HR = 1.77, p = .09). CONCLUSIONS: Children with ES ≤5 years of age have a distinct favorable clinical presentation. However, age is not an independent prognostic factor for survival outcomes when adjusted for confounders.

Treatment differences and long-term outcomes in adults and children with Ewing sarcoma.

INTRODUCTION: Ewing sarcoma is an aggressive malignancy primarily affecting children and adolescents. Limited research is available on treatment practices, clinical course, and survival in adults. METHODS: A multi-institution retrospective cohort study of all adults (>18 years) and children (≤18 years) with Ewing sarcoma treated in British Columbia, Canada between January 01, 2000 and December 31, 2018. RESULTS: One-hundred seven individuals (66 adults, 41 children) were included in the analysis. 5-year OS was 58 % in adults and 75 % in children. For individuals with local disease, 5-year OS was 74 % in adults and 84 % in children. Adult status was associated with impaired PFS (HR, 1.8; 95 % CI, 1.0 - 3.1, p=0.04) and OS (HR, 1.8; 95 % CI, 0.9 - 3.5; p=0.088). A Charlson Comorbidity Index (CCI) ≥3 was associated with impaired survival in adults and children (HR, 3.9, 95 % CI, 2.0 - 7.5; p=<0.001); baseline CCIs were not significantly different between groups. Most adults (61/66; 92 %) and all children (41/41; 100 %) received systemic treatment with no significant difference in mean lines of therapy, treatment modalities or agents. Most children received interval-compressed chemotherapy (35/41; 85 %) compared to adults (19/61; 29 %; p=<0.001). Interval-compression was not significantly associated with improved survival in adults with local disease (HR, 0.51; 95 % CI 0.1 - 2.3; p=0.373). Children more often initiated treatment within 28 days of diagnosis (31/33; 94 %) compared to adults (41/64; 64 %, p=0.001). Treatment within 28 days was associated with improved survival in the entire cohort (HR, 2.04 95 % CI, 1.1 - 3.9; p = 0.03). This association was preserved in subanalysis of individuals with local disease (HR, 5.4; 95 % CI, 1.9 - 15; p = 0.001) and only adults (HR, 5.3, 95 % CI, 1.7 - 17; p = 0.005). DISCUSSION: Survival for adults with Ewing sarcoma is inferior to children despite similarities in presentation, tumour characteristics and treatments. Further studies on the value of interval-compression in adults are required. Timely initation of treatment should be a priority for this disease.

[Treatment of pediatric bone tumors around the knee]. / Behandlung kniegelenksnaher Knochentumoren im Wachstumsalter.

Primary bone tumors are rare but more frequently seen during childhood and with predilection for the distal femur and proximal tibia. Therapy of benign tumors-if indicated-includes surgical resection in most cases, whereas malignant bone tumors such as osteo- and Ewing's sarcomas are treated with chemotherapy, wide resection and/or radiation therapy (Ewing's sarcoma). The reconstruction of emerging bone defects is significantly influenced by surgeon-related preferences and tumor-associated factors, respectively. Double-barrel vascularized fibula grafts or extracorporeally irradiated autografts in combination with a free fibula transplant are preferred biological reconstruction techniques around the knee joint. In cases in which the knee joint cannot be preserved, reconstruction is performed using tumor endoprostheses, but potentially emerging leg length discrepancies after resection of a potent physis must be taken into account. In considerably young patients, rotationplasty might represent a viable option with promising functional results.

Ewing sarcoma presenting in the lung: a case report.

BACKGROUND: Ewing sarcoma is a malignant round-cell tumor that primarily affects bones in children. It can also arise in extraosseous tissues, such as the lung, kidneys, and liver. The presentation symptoms of Ewing sarcoma may include cough, dyspnea, and chest pain. CASE PRESENTATION: This report details the history of a 15-year-old Syrian boy with a previous diagnosis of Hodgkin lymphoma who presented with chronic shoulder pain. Imaging studies revealed an 80 mm mass in the apex of the left lung, which was confirmed through histopathological examination to be Ewing sarcoma following a computed-tomography-guided biopsy. The patient received multiple cycles of chemotherapy and subsequently underwent surgical resection of the remaining mass. CONCLUSIONS: This case highlights the rare occurrence of Ewing sarcoma in the lung and the unusual clinical presentation of shoulder pain without other accompanying symptoms.

68 Ga-DOTA-IBA PET/CT and 18 F-FDG PET/CT in Ewing Sarcoma.

ABSTRACT: A 29-year-old man with Ewing sarcoma in the right ankle underwent 68 Ga-DOTA-IBA PET/CT and 18 F-FDG PET/CT, both of which showed high radiotracer activity for the primary tumor. Interestingly, bone metastases were detected early using 68 Ga-DOTA-IBA PET/CT for the sixth thoracic vertebrae and with 18 F-FDG PET/CT for the bilateral humerus. Higher uptake of 68 Ga-DOTA-IBA was found in both primary and metastatic sites of Ewing sarcoma. 177 Lu-DOTA-IBA may be one of the possible therapies for metastatic or recurrent Ewing sarcoma.

EWS-FLI1 and Activator Protein-1 (AP-1) Reciprocally Regulate Extracellular-Matrix Proteins in Ewing sarcoma Cells.

Ribonucleotide reductase (RNR) is the rate-limiting enzyme in the synthesis of deoxyribonucleotides and the target of multiple chemotherapy drugs, including gemcitabine. We previously identified that inhibition of RNR in Ewing sarcoma tumors upregulates the expression levels of multiple members of the activator protein-1 (AP-1) transcription factor family, including c-Jun and c-Fos, and downregulates the expression of c-Myc. However, the broader functions and downstream targets of AP-1, which are highly context- and cell-dependent, are unknown in Ewing sarcoma tumors. Consequently, in this work, we used genetically defined models, transcriptome profiling, and gene-set -enrichment analysis to identify that AP-1 and EWS-FLI1, the driver oncogene in most Ewing sarcoma tumors, reciprocally regulate the expression of multiple extracellular-matrix proteins, including fibronectins, integrins, and collagens. AP-1 expression in Ewing sarcoma cells also drives, concurrent with these perturbations in gene and protein expression, changes in cell morphology and phenotype. We also identified that EWS-FLI1 dysregulates the expression of multiple AP-1 proteins, aligning with previous reports demonstrating genetic and physical interactions between EWS-FLI1 and AP-1. Overall, these results provide novel insights into the distinct, EWS-FLI1-dependent features of Ewing sarcoma tumors and identify a novel, reciprocal regulation of extracellular-matrix components by EWS-FLI1 and AP-1.

Prion-like domain mediated phase separation of ARID1A promotes oncogenic potential of Ewing's sarcoma.

Liquid-liquid phase separation (LLPS) facilitates the formation of membraneless organelles within cells, with implications in various biological processes and disease states. AT-rich interactive domain-containing protein 1A (ARID1A) is a chromatin remodeling factor frequently associated with cancer mutations, yet its functional mechanism remains largely unknown. Here, we find that ARID1A harbors a prion-like domain (PrLD), which facilitates the formation of liquid condensates through PrLD-mediated LLPS. The nuclear condensates formed by ARID1A LLPS are significantly elevated in Ewing's sarcoma patient specimen. Disruption of ARID1A LLPS results in diminished proliferative and invasive abilities in Ewing's sarcoma cells. Through genome-wide chromatin structure and transcription profiling, we identify that the ARID1A condensate localizes to EWS/FLI1 target enhancers and induces long-range chromatin architectural changes by forming functional chromatin remodeling hubs at oncogenic target genes. Collectively, our findings demonstrate that ARID1A promotes oncogenic potential through PrLD-mediated LLPS, offering a potential therapeutic approach for treating Ewing's sarcoma.

Prognostic factors and outcome of relapsed/progressive pediatric Ewing sarcoma: single-center 10-year experience.

BACKGROUND: Ewing sarcoma (ES) is the second most common primary malignant bone tumor in children and adolescents. Despite more intensive chemotherapy regimens and improved local control therapy, there is still a considerable rate of recurrent/progressive disease. METHODS: A retrospective study of 50 relapsed/progressive ES patients who were treated at the National Cancer Institute (NCI), Cairo University, during the period from 1st of January 2008 to the end of December 2018, to assess different prognostic variables and disease outcomes. RESULTS: Out of fifty eligible cases, 32 patients (64%) had disease recurrence, and 18 (36%) developed disease progression on treatment. The median follow-up period was 7.4 months. The median overall survival (OS) was 7.5 months, and the cumulative OS was 64% at 6 months and 32.6% at 1 year. The cumulative event-free survival (EFS) was 41.3% at 6 months and 22.3% at 1 year. Patients with disease recurrence had better OS and EFS than patients with disease progression (p = 0.019). Patients who underwent local control at relapse/progression had a significantly better outcome than patients who received chemotherapy only (p < 0.001). Recurrence > 2 years from initial diagnosis was the only independent predictor of better survival outcome. CONCLUSIONS: Patients with relapsing/progressive ES portended a poor outcome, with disease progression on treatment faring worse than relapse. Better outcome was observed in patients who experienced recurrence > 2 years after diagnosis, patients with disease recurrence rather than disease progression on treatment, and patients who underwent local control along with intensive chemotherapy.

Ceramide-induced cleavage of GPR64 intracellular domain drives Ewing sarcoma.

Ewing sarcoma is a cancer of bone and soft tissue in children and young adults primarily driven by the EWS-FLI1 fusion oncoprotein, which has been undruggable. Here, we report that Ewing sarcoma depends on secreted sphingomyelin phosphodiesterase 1 (SMPD1), a ceramide-generating enzyme, and ceramide. We find that G-protein-coupled receptor 64 (GPR64)/adhesion G-protein-coupled receptor G2 (ADGRG2) responds to ceramide and mediates critical growth signaling in Ewing sarcoma. We show that ceramide induces the cleavage of the C-terminal intracellular domain of GPR64, which translocates to the nucleus and restrains the protein levels of RIF1 in a manner dependent on SPOP, a substrate adaptor of the Cullin3-RING E3 ubiquitin ligase. We demonstrate that both SMPD1 and GPR64 are transcriptional targets of EWS-FLI1, indicating that SMPD1 and GPR64 are EWS-FLI1-induced cytokine-receptor dependencies. These results reveal the SMPD1-ceramide-GPR64 pathway, which drives Ewing sarcoma growth and is amenable to therapeutic intervention.

Extraskeletal Ewing Sarcoma Disguised as a Vascular Malformation.

Extraskeletal Ewing sarcoma (EES) is a rare entity, accounting for only 3% of lesions encountered in upper extremity. We present two paediatric patients, who were initially diagnosed with a vascular malformation based on clinical assessment and imaging. Final histopathology revealed Ewing sarcoma of soft tissue origin, confirmed by immunohistochemical analysis. Hand surgeons, who are routinely approached for a myriad of hand pathologies, should be wary and consider EES as a differential when treating such lesions. A multidisciplinary approach with an appropriate treatment algorithm can help in a speedy diagnosis, improving the long-term prognosis of the disease. Level of Evidence: Level V (Therapeutic).

SETD8 inhibits apoptosis and ferroptosis of Ewing's sarcoma through YBX1/RAC3 axis.

Ewing's sarcoma (ES) represents a rare yet exceedingly aggressive neoplasm that poses a significant health risk to the pediatric and adolescent population. The clinical outcomes for individuals with relapsed or refractory ES are notably adverse, primarily attributed to the constrained therapeutic alternatives available. Despite significant advancements in the field, molecular pathology-driven therapeutic strategies have yet to achieve a definitive reduction in the mortality rates associated with ES. Consequently, there exists an imperative need to discover innovative therapeutic targets to effectively combat ES. To reveal the mechanism of the SETD8 (also known as lysine methyltransferase 5A) inhibitor UNC0379, cell death manners were analyzed with different inhibitors. The contributions of SETD8 to the processes of apoptosis and ferroptosis in ES cells were evaluated employing the histone methyltransferase inhibitor UNC0379 in conjunction with RNA interference techniques. The molecular regulatory mechanisms of SETD8 in ES were examined through the application of RNA sequencing (RNA-seq) and mass spectrometry-based proteomic analysis. Moreover, nude mouse xenograft models were established to explore the role of SETD8 in ES in vivo. SETD8, a sole nucleosome-specific methyltransferase that catalyzes mono-methylation of histone H4 at lysine 20 (H4K20me1), was found to be upregulated in ES, and its overexpression was associated with dismal outcomes of patients. SETD8 knockdown dramatically induced the apoptosis and ferroptosis of ES cells in vitro and suppressed tumorigenesis in vivo. Mechanistic investigations revealed that SETD8 facilitated the nuclear translocation of YBX1 through post-transcriptional regulatory mechanisms, which subsequently culminated in the transcriptional upregulation of RAC3. In summary, SETD8 inhibits the apoptosis and ferroptosis of ES cells through the YBX1/RAC3 axis, which provides new insights into the mechanism of tumorigenesis of ES. SETD8 may be a potential target for clinical intervention in ES patients.