Ewing Sarcoma Patients Research Articles

Chimeric protein EWS::FLI1 drives cell proliferation in Ewing Sarcoma via aberrant expression of KCNN1/SK1 and dysregulation of calcium signaling.

Ewing sarcoma (ES) is characterized by EWS::FLI1 or EWS::ERG fusion proteins. Knowing that ion channels are involved in tumorigenesis, this work aimed to study the involvement of the KCNN1 gene, which encodes the SK1 potassium channel, in ES development. Bioinformatics analyses from databases were used to study KCNN1 expression in patients and cell lines. Molecular approaches and in vitro assays were used to study the transcriptional regulation of KCNN1 and its involvement in the regulation of ES cell proliferation. KCNN1 is overexpressed in ES patient biopsies, and its expression is inversely correlated with patient survival. EWS::FLI1, like EWS::ERG, promotes KCNN1 and SK1 expression, binding to GGAA microsatellites near the promoter of KCNN1 isoforms. KCNN1 is involved in the regulation of ES cell proliferation, with its silencing being associated with a slowing of the cell cycle, and its expression modulates membrane potential and therefore calcium flux. These results highlight that KCNN1 is a direct target of EWS::FLI1 and EWS::ERG and demonstrate that KCNN1 is involved in the regulation of intracellular calcium activity and ES cell proliferation, making it a promising therapeutic target in ES.

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.

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.

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

BackgroundEwing sarcoma (EwS) is a highly malignant and heterogeneous tumor. Exploring clinicopathological characteristics and genetic features of EwS is critical for prognosis and treatment regimen.MethodsClinicopathological characteristics and genetic features of young (≤ 30y) and senior (> 30y) EwS patients were analyzed based on histology, phenotype, and next-generation sequencing (NGS) detection.ResultsThe 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.ConclusionClinicopathological 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.

Circumventing resistance within the Ewing sarcoma microenvironment by combinatorial innate immunotherapy

BackgroundPediatric patients with recurrent/metastatic Ewing sarcoma (ES) have a dismal 5-year survival. Novel therapeutic approaches are desperately needed. Natural killer (NK) cell number and function are low in ES patient...

Ewing’s Sarcoma Presenting in the Paranasal Sinus – A Case Report

Abstract Rationale: The aim of this study is to raise awareness among dentists regarding a potential outcome associated with the rapid growth of facial swellings. Patient Concerns: We present a case of Ewing’s sarcoma (ES) in a 23-year-old male who presented with a rapidly progressive swelling in the left maxillary region over six weeks. Diagnosis: There was no significant intraoral dental finding other than a missing left upper first molar. Panoramic imaging initially suggested chronic sinusitis, but the swelling persisted despite treatment. A subsequent cone-beam computed tomography (CBCT) scan revealed a soft-tissue tumour affecting multiple sinuses, confirmed by an open biopsy as a small round cell tumour. Immunohistochemistry was used for precise diagnosis due to biopsy sample limitations and tumour variability. Treatment: The patient’s case was reviewed by our institution’s tumour board. One month after diagnosis, chemotherapy began with alternating drugs for a total of 6 cycles. Outcomes: A follow-up Positron Emission Tomography (PET)/Computed Tomography (CT) scan after two months of chemotherapy showed resolution of the hypermetabolic mass on the left side without evidence of metastatic disease. The patient is currently under regular follow-up. Take-Away Lessons: Dentists should be vigilant for rapidly expanding oral or facial swellings. Early and accurate diagnosis can improve clinical management and survival rates for ES patients.

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.

1755P Multimodal therapy in first line treatment of very high risk Ewing sarcoma patients: Results of the French prospective multicenter COMBINAIR3 phase II trial

1755P Multimodal therapy in first line treatment of very high risk Ewing sarcoma patients: Results of the French prospective multicenter COMBINAIR3 phase II trial

747: Toxicity/outcome of Definitive Ewing's sarcoma patients treated with PBT at the Christie.

747: Toxicity/outcome of Definitive Ewing's sarcoma patients treated with PBT at the Christie.

Mecapegfilgrastim for prophylaxis of febrile neutropenia in children and adolescents with rhabdomyosarcoma or Ewing sarcoma: a prospective, single-arm, pilot study

BackgroundThe chemotherapy regimens recommended for both rhabdomyosarcoma (RMS) and Ewing sarcoma (ES) patients are myelosuppressive and can reduce the absolute neutrophil count (ANC) and subsequently increase the risk of febrile neutropenia (FN). However, only a few studies have focused on the efficacy and safety of granulocyte-colony stimulating factor (G-CSF) drugs in pediatric and adolescent patients with RMS and ES. Our objective was to investigate the efficacy and safety of mecapegfilgrastim, a biosimilar of pegfilgrastim, in prophylaxis of FN for pediatric and adolescent patients with RMS or ES.MethodsIn this single-arm, single-center, prospective study, pediatric and adolescent patients with RMS or ES were enrolled to receive either VAC (vincristine, cyclophosphamide, dactinomycin) regimen or VDC (vincristine, cyclophosphamide, doxorubicin) regimen in a 3-week cycle, followed by treatment with mecapegfilgrastim (100 μg/kg, maximum 6 mg) given at 24 h after completing chemotherapy. The primary endpoint was the incidence rate of FN. Secondary endpoints included the incidence rate of grade 4 neutropenia, duration of ANC ≤ 0.5 × 109/L, incidence rate of chemotherapy delay or reduction, use of antibiotics, and safety profile.ResultsIn total, 2 of the 30 (6.7%, 95% CI: 0.82–22.07) patients experienced FN after the first cycle of chemotherapy. Eight (26.7%, 95% CI: 12.28–45.89) patients experienced grade 4 neutropenia after receiving prophylactic mecapegfilgrastim. Eight patients experienced ANC ≤ 0.5 × 109/L with a median duration of 4.5 days; among them, 6 patients reached the lowest point of their ANC level on day 7, and 5 of them recovered by day 10. No dose reductions, delays, or discontinuation of chemotherapy was reported. Twenty-one (70.0%) patients received antibiotics during the treatment period. No patient experienced FN in the 0–5 years and the 13–18 years groups, and 2 patients experienced FN in the 6–12 years group. Two patients, 6 patients, and no patient experienced grade 4 neutropenia in the 0–5 years, 6–12 years, and 13–18 years groups, respectively.ConclusionMecapegfilgrastim showed acceptable efficacy and safety profile in pediatric and adolescent patients with RMS or ES. Further randomized studies with large sample size are warranted.Trial registrationThis clinical trial was registered at Chictr.org.cn (No.ChiCTR1900022249). Registered on March 31, 2019.

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.

Emerging therapies in Ewing sarcoma.

There is an unmet need to improve outcomes for patients for Ewing sarcoma, a rare, aggressive sarcoma with a peak incidence in adolescents and young adults (AYA). Current therapy at diagnosis involves multiagent chemotherapy and local therapy, but despite intensification of treatment, those with metastases at diagnosis and recurrent disease have poor outcomes. Improved understanding of Ewing sarcoma biology has identified novel targets with promising activity in Ewing sarcoma patients, including tyrosine kinase inhibitors that are now undergoing evaluation as combination and maintenance therapy. Other emerging therapies include those that target the EWSR1::FLI1 fusion oncoprotein, and act on DNA damage, cell cycle and apoptotic pathways. Immunotherapeutic approaches, particularly CAR-T-cell therapy directed at GD2, also hold promise. Recent collaborative clinical trials that have defined an international standard of care for patients with newly diagnosed Ewing sarcoma and novel platform studies with adaptive designs offer unique opportunities to investigate these therapies inclusive of all ages. Close international collaboration between clinicians and biologists will allow us to prioritize promising emerging therapies and develop biomarkers to facilitate their incorporation into standard of care and more rapidly translate into benefit for Ewing sarcoma patients.

Is bone marrow biopsy and aspiration still mandatory when 18F-FDG PET/CT is available for the initial assessment of bone marrow metastasis in pediatric Ewing sarcoma?

To compare the diagnostic value of 18F-fluorodeoxyglucose-positron emission tomography/computed tomography (18F-FDG PET/CT) and bone marrow biopsy and aspiration (BMBA) for evaluating bone marrow metastases (BMM) in newly diagnosed pediatric Ewing sarcoma (ES). To assess the diagnostic accuracy of 18F-FDG PET/CT against BMBA for marrow infiltration in ES patients, a retrospective analysis encompassed 103 ES patients from the Children's Hospital of Chongqing Medical University, spanning nine years, who underwent both 18F-FDG PET/CT and BMBA at the point of diagnosis. The median age of this study was 9.3(15 days to 17.1 years), 52(50.5%) patients were male. Among the cohort, 8 subjects received a BMM diagnosis via marrow cytology or histopathology, concomitant with positive 18F-FDG PET/CT findings. An additional 4 patients were identified with BMM solely through 18F-FDG PET/CT. No cytologically or histologically positive BMM were found in PET/CT-negative patients. Therefore, within this selected sample group, the 18F-FDG PET/CT imaging technique exhibited sensitivity of 100% and specificity of 95.8%. The five-year overall survival rate decreased from 57.5% among the entire cohort of patients to a mere 30% for individuals suffering from BMM. Given these findings, the prevailing reliance on BMBA warrants reevaluation when 18F-FDG PET/CT is available, potentially heralding a shift towards less invasive diagnostic modalities in the management of ES.

A reduction in tumor volume exceeding 65% predicts a good histological response to neoadjuvant chemotherapy in patients with Ewing sarcoma.

No consensus exists for tumor volume response criteria in patients with Ewing sarcoma. This study aimed to identify an optimal cutoff for predicting a good histological response by analyzing tumor volume changes and tumor necrosis after neoadjuvant chemotherapy. We performed a retrospective analysis of 184 Ewing sarcoma patients, analyzing tumor volume changes before and after neoadjuvant chemotherapy. Patients were divided into two groups based on histological response: good (tumor necrosis ≥ 95%) and poor (tumor necrosis < 95%) responders. The receiver operating characteristic (ROC) area under the curve (AUC) method was used to determine the optimal thresholds for predicting the histological response. Additionally, the prognostic value of this cutoff for relapse-free survival was assessed. Out of 184 patients, 83 (45%) had tumor necrosis ≥ 95%, while 101 (55%) had tumor necrosis < 95%. ROC analysis identified the optimal cutoff for a good histological response as over 65% tumor volume reduction (AUC = 0.69; p < 0.001). Patients with volume reduction of ≥ 65% had a higher likelihood of a good histological response than those with lesser reductions (p = 0.004; odds ratio = 2.61). Multivariable analysis indicated a correlation between poor histological response and reduced relapse-free survival (hazard ratio = 2.17; p = 0.01), while tumor volume reduction itself did not impact survival. We reported that a tumor volume reduction of ≥ 65% was able to predict a good histological response in Ewing sarcoma patients. We recommend preoperative tumor volume assessment to identify patients at greater risk for poor histological response who could benefit from more intensive chemotherapy protocols or additional radiotherapy.

Infiltration of Round Blue Cell Tumors in Bone Marrow

Objective: To identify different types of round blue cell tumors on bone marrow biopsy and their pattern of marrow infiltration. Methodology: This cross-sectional descriptive study was conducted at the Department of Hematology, Armed Forces Institute of Pathology (AFIP), Rawalpindi, from July 2021 to December 2021. A total of 60 diagnosed cases of round blue cell tumors were included. Patients with acute lymphoblastic leukemia (ALL) and those receiving treatment for round blue cell tumors were excluded. Bone marrow aspiration and biopsy were performed. Peripheral film results, clinical observations, and patterns of marrow infiltration of round blue cell malignancies were analyzed using Statistical Package for the Social Sciences (SPSS) version 23. Results: The study revealed a male to female ratio of 2:1, with 40 (66.6%) males and 20 (33.3%) females. The overall average age was 5.69 ± 5.0 years. Ewing sarcoma and rhabdomyosarcoma patients did not exhibit infiltration, while three instances of retinoblastoma (9.37%) and two cases of neuroblastoma (10.52%) did. Immunohistochemistry (IHC) results for synaptophysin and chromogranin were positive for retinoblastoma and neuroblastoma, while S100 results were positive for neuroblastoma infiltration and negative for retinoblastoma. Both retinoblastoma and neuroblastoma showed diffuse, focal, and interstitial patterns of infiltration on trephine biopsy. Conclusion: Small round blue cell tumors were noted in bone marrow infiltration in 5 (8.33%) cases. Early detection of malignant cancers necessitates appropriate medical care, and in more severe cases, the need for neoadjuvant chemotherapy.

Abstract 1560: In vivo CRISPR/Cas9 transcriptional activation screen leads to discovery of INAFM2, a novel driver of metastasis

Abstract Metastasis is the main cause of mortality in cancer patients and accounts for about 90% of cancer deaths, which has not changed in the past 50 years. This indicates a significant need for further study of metastasis pathways to find novel druggable targets. Ewing sarcoma (ES) is an aggressive childhood cancer that occurs in the bones or soft tissue. The five-year survival rate for Ewing sarcoma patients diagnosed with metastatic disease is still only 25%, making ES a good model for studying metastasis. We performed a genome-wide CRISPR/Cas9 transcriptional activation screen in a zebrafish xenograft model to discover genes whose activation leads to increased metastasis. The screen identified a number of genes that may accelerate ES metastasis; we chose INAFM2 for further study because multiple unique INAFM2-targeting gRNAs were enriched in the screen and we discovered a potential link to metastasis and patient survival in publicly available clinical data. Overexpression of INAFM2 in six different cancer cell lines (four ES, one hepatocellular carcinoma, and one stomach adenocarcinoma) caused increased cell migration and chemotaxis in vitro, and increased intravasation in zebrafish xenografts. INAFM2 knockdown in four cancer cell lines (two ES, one clear cell renal cell carcinoma, and one stomach adenocarcinoma) decreased chemotaxis and rescue of INAFM2 expression restored the cells’ ability to migrate. Analysis of patient tumor RNA sequencing data from many different types of cancers revealed correlations between INAFM2 expression and both an increased metastatic phenotype and poor patient survival. Further in vivo studies by tail vein injection of ES cells in immunodeficient mice demonstrated significantly increased gross metastases with INAFM2 overexpression and decreased gross metastases with INAFM2 knockdown compared to the respective control groups. This provides strong evidence for a substantial role of INAFM2 in cancer metastasis. Human INAFM2 is an unstudied gene and our preliminary work has revealed that the INAFM2 protein localizes to the cell membrane, is glycosylated, and may be involved in Wnt and/or MAPK pathway signaling. Inafm2 silencing by morpholino in zebrafish embryos lead to significant mortality, necrosis, and developmental delays/defects including severe cardiac edema. Current studies are focused on further discerning the molecular pathways that mediate the role of INAFM2 in promoting metastasis using in vitro and in vivo models as well as characterizing the functional significance of the direct protein binding partners and post-translational modifications for INAFM2. Citation Format: Anna Molotkova, Emre Deniz, Matthew Swift, Eric Glasgow, Jeffrey Toretsky, Aykut Üren. In vivo CRISPR/Cas9 transcriptional activation screen leads to discovery of INAFM2, a novel driver of metastasis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1560.

Abstract 1081: A role for the oncogenic driver fusion protein EWS-FLI1 in the targeting of DR5 by INBRX-109 in Ewing sarcoma

Abstract Background: Tumor necrosis factor receptor superfamily member 10b (TNFRSF10b, also known as DR5) agonists are attractive targeted agents for cancer cells because these agents activate cellular apoptosis. Ewing sarcoma (ES) is a bone and soft-tissue sarcoma occurring in adolescence defined by a t(11;22)(q24;q12) balanced chromosomal translocation that results in chimeric transcription factor and oncogenic driver protein, EWS-FLI1. Independent studies and unbiased cell line screens have reported ES to be sensitive to DR5 targeting. INBRX-109 is a tetravalent, DR5-targeted antibody. Here, we analyzed the sensitivity of ES models to DR5 targeting by INBRX-109 and explored how the EWS-FLI1 transcriptional program impacts the continuum of sensitivity-resistance to this targeting. Methods: In a panel of 11 ES lines, in vitro sensitivity was assessed to both single agent and INBRX-109 combinations. A screen of 1,363 FDA approved compounds identified cooperative combinations that were prioritized mechanistically. Differential sensitivity for single agent and in combination with irinotecan was confirmed in vivo in xenograft models. Resistant clones were isolated from in vivo experiments and evaluated for DR5 expression and sensitivity. Cellular factors associated with sensitivity and resistance were determined by siRNA knockdown and Cleavage Under Targets and Tagmentation assay (CUT and Tag). Results: ES models showed variable sensitivity to INBRX-109, with a GI90 as low as 10 picomolar in some models. All models showed robust expression of DR5, but absolute expression of DR5 did not correlate with sensitivity. In vitro sensitivity was replicated in vivo, with all 7 mice bearing RD-ES xenografts demonstrating initial complete tumor regression and 3 of 7 mice demonstrating no recurrence beyond 90 days. Importantly, cells isolated from recurrent tumors showed a novel mechanism of resistance: direct repression of DR5 by EWS-FLI1. INBRX-109 was ineffective as a single agent at 10 nM in resistant ES models. However, there was striking synergy in vitro with SN38, the active metabolite of irinotecan, and this effect translated into tumor regressions of a resistant TC32 xenograft in vivo. The FDA compound screen captured novel synergy with a panel of agents. Conclusion: INBRX-109 is an exciting candidate for ES as a single agent in subsets of tumors or in combination with irinotecan, which is currently being evaluated in the clinic. Investigation of the exact relationship between EWS-FLI1 and sensitivity to DR5 targeting is ongoing. Initial findings suggest EWS-FLI1, combined with other disease modifying mutations, is a key mediator of this sensitivity. Further, EWS-FLI1 plays a direct role repressing DR5 in the setting of therapeutic challenge in one model in vivo. These findings highlight the potential for INBRX-109 in combination with irinotecan or novel candidates as therapies for ES patients. Citation Format: Curtis C. Parker, Lauren M. Gaetano, Elissa A. Boguslawski, Seneca Kinn-Gurzo, Rebecca Kaufman, Matthew C. Stout, Chase Deveraux, Patrick J. Grohar. A role for the oncogenic driver fusion protein EWS-FLI1 in the targeting of DR5 by INBRX-109 in Ewing sarcoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1081.

The significance of surveillance imaging in children with Ewing sarcoma and osteosarcoma

Primary bone tumors in children and adolescents, while rare, pose significant challenges in diagnosis and management. Children treated for Ewing sarcoma and osteosarcoma are offered a 5-year follow-up program after end of treatment, including radiological surveillance of primary location of tumor and the lungs. There is no consensus regarding how often and how the children should be followed with radiological imaging. This retrospective descriptive study of 69 patients (34 with Ewing sarcoma and 35 with osteosarcoma) investigated the consequences of abnormal findings in 1279 follow-up images. Nine relapses were detected, 4 in the Ewing group (3 local and 1 pulmonary) and 5 in the osteosarcoma group (1 local and 4 pulmonary). Of these, only two patients exhibited symptomatic relapses, with the remainder identified through imaging. The positive predictive value for relapse detection was 0.44 in the Ewing group, and 0.5 in the osteosarcoma group. In the Ewing sarcoma patient image follow-up program, the probability of anomaly detection was 12% (95% CI, 10–15). For osteosarcoma patients, the likelihood was 6% (95% CI, 4–8). Our data indicates that abnormal findings on follow-up images rarely represents relapse of tumor. As the surveillance protocol differs between the patient groups, wherein Ewing sarcoma patients primarily are monitored through MRI while osteosarcoma patients are predominantly tracked via X-rays, there is an increased occurrence of incidental findings in the first group. However, it is imperative to interpret imaging data in conjunction with clinical information, avoiding isolated reliance on imaging results when making treatment decisions.

AURKA inhibition induces Ewing’s sarcoma apoptosis and ferroptosis through NPM1/YAP1 axis

Ewing’s sarcoma (ES) is a rare and highly aggressive malignant tumor arising from bone and soft tissue. Suffering from intractable or recurrent diseases, the patients’ therapy options are very limited. It is extremely urgent to identify novel potential therapeutic targets for ES and put them into use in clinical settings. In the present study, high-throughput screening of a small molecular pharmacy library was performed. The killing effect of the Aurora kinase A (AURKA) inhibitor TCS7010 in ES cells was identified, and AURKA was selected as the research object for further study. Disparate suppressants were adopted to study the cell death manner of TCS7010. TCS7010 and RNA silencing were used to evaluate the functions of AURKA in the apoptosis and ferroptosis of ES cells. Co-immunoprecipitation assay was used to investigate the correlation of AURKA and nucleophosmin1 (NPM1) in ES. Nude-mice transplanted tumor model was used for investigating the role of AURKA in ES in vivo. Investigations into the protein activities of AURKA were conducted using ES cell lines and xenograft models. AURKA was found to be prominently upregulated in ES. The AURKA expression level was remarkably connected to ES patients’ shorter overall survival (OS) and event-free survival (EFS). Furthermore, AURKA inhibition markedly induced the apoptosis and ferroptosis of ES cells and attenuated tumorigenesis in vivo. On the part of potential mechanisms, it was found that AURKA inhibition triggered the apoptosis and ferroptosis of ES cells through the NPM1/Yes1 associated transcriptional regulator (YAP1) axis, which provides new insights into the tumorigenesis of ES. AURKA may be a prospective target for clinical intervention in ES patients.

One Hundred Percent Tumor Necrosis is Associated with Survival in Ewing Sarcoma

Background and Objectives:Ewing sarcoma is a primary malignancy affecting both bone and soft tissue. Following preoperative chemotherapy and surgical resection, histologic response (tumor necrosis) is correlated with patient survival. The most prognostic cutoff for tumor necrosis continues to be debated. The objective of this study was to explore several cutoffs and determine their prognostic value in a contemporary cohort of Ewing sarcoma patients.&#x0D; Methods:The National Cancer Database was used to identify 564 patients with osseous and soft tissue tumors in the Ewing sarcoma family from 2010 to 2015. All patients had documented preoperative chemotherapy, surgical resection, and vital status. Survival was stratified by tumor necrosis using Kaplan Meier analysis. 356 patients with osseous tumors were included in multivariate logistic and cox regression analyses to identify predictors of histologic response and survival, respectively.&#x0D; Results:In a combined soft tissue and osseous tumor cohort, there was a significant difference (p = 0.01, log-rank test) in overall survival between patients with 100% necrosis and patients with less than 100% necrosis. This was observed over the 5-year study period. Other cutoffs were not statistically different. In patients with osseous tumors, less than 100% necrosis was negatively associated with survival (HR 3.48 [95% CI 1.19-10.13]; p&lt; 0.05), with only skip metastasis having a stronger negative association (HR 4.31 [95% CI 1.22-15.29]; p&lt; 0.05). Male sex (OR 0.50 [95% CI 0.28-0.90]; p&lt;0.05), tumors located in the axial skeleton (OR 0.30 [95% CI 0.12- 0.77]; p&lt;0.05), and positive surgical margins (OR 0.28 [95% CI 0.08-0.95]; p&lt;0.05) were negatively associated with 100% necrosis.&#x0D; Conclusion and Implications:A cutoff of 100% tumor necrosis was associated with improved survival in Ewing sarcoma. This association was strong relative to other commonly used prognostic factors in osseous cases and is a valuable tool to counsel patients and guide future clinical trials.