Preclinical models for the study of pediatric solid tumors: focus on bone sarcomas.

Sarcomas comprise between 10-15% of all pediatric malignancies. Osteosarcoma and Ewing sarcoma are the two most common pediatric bone tumors diagnosed in children and young adults. These tumors are commonly treated with surgery and/or radiation therapy and combination chemotherapy. However, there is a strong need for the development and utilization of targeted therapeutic methods to improve patient outcomes. Towards accomplishing this goal, pre-clinical models for these unique malignancies are of particular importance to design and test experimental therapeutic strategies prior to being introduced to patients due to their origination site and propensity to metastasize. Pre-clinical models offer several advantages for the study of pediatric sarcomas with unique benefits and shortcomings dependent on the type of model. This review addresses the types of pre-clinical models available for the study of pediatric solid tumors, with special attention to the bone sarcomas osteosarcoma and Ewing sarcoma.

Real-world experiences in patients with Ewing sarcoma treated at a specialist centre in Turkey.

Objectives: The present study evaluates the clinical outcomes of children, adolescents and adults with Ewing sarcoma and identifies the prognostic factors. Methods: Included in the study were 222 pediatric and adult patients diagnosed with Ewing sarcoma (EwS) who were followed up between 1992 and 2019, and whose data were analyzed retrospectively. Results: The median age of 131 male and 91 female patients included in the study was 13 (1-64). The median follow-up duration of the survivors was 79 months (range, 11-182 months). The 3-year EFS rate of the 222 patients was 34 % (Confidence Interval (CI) (0.158-0.242 %) and the OS rate was 54 % (CI, 0.289-0.590 %). For the non-metastatic patients, the 3-year EFS rate was 47 % and the OS was 68 %, while for the metastatic patients the 3-year EFS rate was 13 % and the OS was 30 %. Of the patient sample, 81 (36, 5 %) survived, of whom 72 were continuously free of disease while the disease persisted in nine, and three developed a secondary neoplasm (2 of whom subsequently died while one survived disease-free). Of the 129 patients who relapsed with metastases and/or local recurrence, eight survived and are disease-free, nine are alive with uncontrolled disease; five were lost to follow-up and 107 died. Conclusion: The findings of the present study suggest metastatic disease at presentation and positive margins after surgery to be of prognostic significance in EwS. Disruptions in aggressive local treatments may reduce the chances of cure in EwS.

Extraosseous Ewing Sarcoma in a 28-Year-Old Male: A Case Report and Literature Review.

Ewing sarcoma (ES) is an uncommon and highly aggressive bone malignancy that predominantly occurs in children and young adults. Extraosseous Ewing sarcoma (EES), an even rarer variant, can present in the soft tissues instead of bone. In this case report, we detail a previously healthy 28-year-old male presenting with an isolated enlarged left inguinal lymph node, subsequently diagnosed as EES. The patient presented with a three-month history of a non-tender, gradually enlarging lump in the left groin. Fine needle aspiration revealed a small round blue cell tumor with a high Ki-67 score, and subsequent excisional biopsy identified a rare genetic fusion mutation. Postoperative positron emission tomography (PET)/computed tomography (CT) scan did not show any fludeoxyglucose F18 (FDG) uptake lesions to suggest residual malignancy. The patient is currently awaiting chemotherapy. Throughout the discussion of this case, we highlight the importance of considering EES in the differential diagnosis of isolated lymph node enlargement, the role of genetic testing in diagnosis, and the treatment modalities offered.

Ewing sarcoma of the uterus: A case report.

A case is described of Ewing sarcoma of the uterus, an atypical presentation of an already rare cancer. A 55-year-old woman presented with abdominal pain, abnormal uterine bleeding and a uterine mass that measured 11 × 10 × 14.5 cm and demonstrated heterogeneous enhancement with possible areas of central necrosis, concerning for sarcoma. She had a complete surgical resection with total abdominal hysterectomy, bilateral salpingo-oophorectomy, omentectomy, bilateral pelvic lymph node dissection, and excision of mesenteric tumor implants. Her final pathology showed primary Ewing sarcoma-primitive neuroectodermal tumor of the uterus with metastatic spread to the peritoneal cavity. She finished 14 cycles of vincristine-doxyrubicin-cyclophosphamide-ifosfamide, etoposide chemotherapy with no evidence of recurrent metastatic disease at 6-month follow-up. Ewing sarcoma is a rare cancer, predominantly seen in adolescents, that typically are of the bone, although in rare instances it can arise from soft tissue; even rarer are presentations in the female genital tract. Even with typical presentations of Ewing sarcoma of the bone, metastatic disease has an overall poor prognosis. The scarcity of cases of metastatic Ewing sarcoma-peripheral neuroendocrine tumors of the uterus makes the condition especially difficult to study. This report describes a case of Ewing sarcoma of the uterus treated by complete surgical resection and aggressive multimodal chemotherapy.

Consensus recommendations for systemic therapies in the management of relapsed Ewing sarcoma: A report from the National Ewing Sarcoma Tumor Board.

Ewing sarcoma (ES) is a malignant tumor of bone and soft tissue that most often occurs in children, adolescents, and young adults. Debate and controversy remain in the management of relapsed/refractory ES (RR-ES). The authors leveraged the expertise assembled by the National Ewing Sarcoma Tumor Board, a multidisciplinary virtual tumor board that meets monthly to discuss challenging cases of ES. In this review, they focus on select topics that apply to the management of patients with RR-ES. The specific topics covered include the initial approach of such patients and discussion of the goals of care, the role of molecular testing, chemotherapy regimens and novel agents to consider, the role of maintenance therapy, and the use of high-dose chemotherapy with autologous stem cell rescue. The data referenced are often limited to subgroup analyses and/or compiled from multiple sources. Although not intended to replace the clinical judgement of treating physicians, these guidelines are intended to support clinicians and provide some clarity and recommendations for the management of patients with RR-ES. PLAIN LANGUAGE SUMMARY: Ewing sarcoma (ES) is a bone and soft tissue cancer that most often occurs in teenagers and young adults. This article uses the experience of the National Ewing Sarcoma Tumor Board, a multi-institution, multidisciplinary virtual tumor board that meets monthly to discuss challenging cases of ES and to address questions related to the treatment of patients with relapsed ES. Although not intended to replace the clinical judgement of treating physicians and limited by available data, these consensus recommendations will support clinicians who treat patients with this challenging malignancy, made even more difficult when it recurs.

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.

Ewing's Sarcoma of Mandible: A Case Report with Review of Literature.

Background: Ewing sarcoma (ES), a rare malignancy, comprises whatever the age, 4-15% of all primary bone tumors. It represents 1% of all malignant tumors in children and is the fourth most common bone malignancy after myeloma, osteosarcoma, and chondrosarcoma. Case description: A 12-year-old boy came to the Oral Surgery Department of Bretonneau Hospital referred by his dentist with a rapidly evolving swelling in the left mandibula for 6 weeks, which was initially diagnosed as a facial cellulitis. Cone beam computed tomography (CBCT) showed a poorly defined, expansile, and osteolytic tumor on the left side of the mandible. Clinical and radiographic findings were in favor of an aggressive primitive bone tumor. A mandibular biopsy under general anesthesia was performed in the Department of Surgical Oncology at Institut Curie in Paris, revealing an ES. Conclusion: Mandibular ES can mimic dental infections when swelling is the main clinical manifestation, which can lead to a delayed diagnosis. A correlation between clinical, radiological, histopathological, and immunohistochemical with cytogenetics is needed to confirm the diagnosis. Moreover, smaller tumors have better survival.Dentists must therefore be aware of the clinical signs of ES in order to quickly refer patients to a specialized department. How to cite this article: Bellut N, Lutz CM, Lesnik M, et al. Ewing's Sarcoma of Mandible: A Case Report with Review of Literature. Int J Clin Pediatr Dent 2024;17(2):187-190.

Cushing's syndrome caused by giant Ewing's sarcoma of the kidney: A case report and review of literature.

BACKGROUND: Primary renal Ewing's sarcoma (ES) is extremely rare, and only two cases causing Cushing's syndrome (CS) have been reported to date. We report that the case of an 18-year-old patient is diagnosed primary renal ES with typical CS characterized by purple stripes, weight gain, and hypertension. CASE SUMMARY: CS was first diagnosed by laboratory testing. A huge tumor was revealed in the kidney following an imaging examination. Moreover, brain and bone metastases were observed. After comprehensive treatment, primarily based on surgery, primary renal ES was pathologically diagnosed with a typical EWSR1-FLI1 genetic mutation through genetic testing. Furthermore, the glucocorticoid level returned to normal. By the ninth postoperative month of follow-up, the patient was recovering well. Cushing-related symptoms had improved, and a satisfactory curative effect was achieved. CONCLUSION: Primary renal ES, a rare adult malignant tumor, can cause CS and a poor prognosis.

Primary Ewing's Sarcoma of the Kidney Mimicking Renal Cell Carcinoma With Widespread Metastasis: A Case Report and a Brief Review of the Literature.

Ewing's sarcoma family of tumors (ESFTs) are a group of small round cell tumors with common morphological and genetic features, including Ewing's sarcoma of bone, primary extra-skeletal Ewing tumors, extraosseous Ewing sarcoma (EES), and Askin tumors. EES presenting as a primary renal mass is an exceedingly uncommon aggressive tumor with limited reported cases in the literature and often mimics other renal malignancies on imaging. We present a case of a 31-year-old man presenting with left flank pain and abdominal fullness of short duration. Radiological imaging studies showed a large heterogenous mass from the left kidney, confirmed to be Ewing's sarcoma on post-operative histopathological examination (HPE) and immunohistochemistry (IHC) studies. Subsequent follow-up showed extensive metastatic disease. EES of the kidney has a nonspecific presentation and imaging appearance necessitating a multi-disciplinary approach comprising radiological imaging with a high index of suspicion, HPE, IHC, and molecular analysis for the correct diagnosis.

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.

Renal Ewing sarcoma with inferior vena cava (IVC) tumor thrombosis; A case report.

Ewing sarcoma (ES) is a rare group of undifferentiated tumors that originate from neuroectoderm. Although the overall prognosis is poor, early diagnosis and treatment by a multidisciplinary team with multimodal therapy can improve outcomes. Therefore, we present a 22-year-old female patient with primary renal ES with tumor thrombosis up to the vena cava who had radical nephrectomy and IVC tumor thrombectomy followed by adjuvant chemotherapy because a preoperative percutaneous biopsy was confirmed the diagnosis.

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

BACKGROUND: The 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. METHODS: In 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. RESULTS: In 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. CONCLUSION: Mecapegfilgrastim 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 REGISTRATION: This clinical trial was registered at Chictr.org.cn (No.ChiCTR1900022249). Registered on March 31, 2019.

Primary Ewing's sarcoma of the intestine: case report and literature review.

Ewing sarcoma (ES)/peripheral primitive neuroectodermal tumor is a highly aggressive malignant tumor that typically presents in bone and soft tissue. Primary ES of the intestine is relatively rare, which poses a challenge in distinguishing it from other primary tumors of the small intestine through imaging. This article details a case study of ES originating in the intestine. Computed tomography (CT) imaging suggested a small intestinal stromal tumor, and so the patient underwent resection of the small bowel and omental tumor. Pathology results confirmed the diagnosis of ES of the small intestine. Following surgery, the patient underwent six cycles of chemotherapy, and a follow-up positron emission tomography-CT revealed widespread dissemination of the disease with intraperitoneal metastasis, ultimately resulting in the death of the patient.

Clinical practice guidelines for the treatment of Ewing sarcoma (Spanish Sarcoma Research Group-GEIS).

Ewing sarcoma is a small round-cell sarcoma characterized by gene fusion involving EWSR1 (or another TET family protein like FUS) and an ETS family transcription factor. The estimated incidence of this rare bone tumor, which occurs most frequently in adolescents and young adults, is 0.3 per 100,000/year. Although only 25% of patients with Ewing sarcoma are diagnosed with metastatic disease, historical series show that this is a systemic disease. Patient management requires multimodal therapies-including intensive chemotherapy-in addition to local treatments (surgery and/or radiotherapy). In the recurrent/refractory disease setting, different approaches involving systemic treatments and local therapies are also recommended as well as patient inclusion in clinical trials whenever possible. Because of the complexity of Ewing sarcoma diagnosis and treatment, it should be carried out in specialized centers and treatment plans should be designed upfront by a multidisciplinary tumor board. These guidelines provide recommendations for diagnosis, staging, and multimodal treatment of Ewing sarcoma.

Innovative Approach to Chest Wall Reconstruction Using Autologous Tissue - The Fascia Lata in Pediatric Patients.

Chest wall reconstruction poses significant challenges. One of those challenges is choosing the correct material for reconstruction. There is debate on using prosthetic materials versus autologous tissues and rigid versus nonrigid materials. This article showcases the novel use of fascia lata for chest wall reconstruction in children.

The Role of Deubiquitinating Enzymes in Primary Bone Cancer.

Bone is a living, intricate, and dynamic tissue providing locomotion and protection of the body. It also performs hematopoiesis and mineral homeostasis. Osteosarcoma (OS), Ewing sarcoma (ES), and chondrosarcoma (CS) are primary bone cancers. OS and ES mostly develop in younger individuals, and CS generally develops in adults. Ubiquitination regulates numerous cellular processes. The deubiquitinating enzymes (DUBs) detach the ubiquitin molecules from the ubiquitin labeled substrate, altering ubiquitinated protein functions and regulating protein stability via various signaling pathways. Protein homeostasis and bone remodeling are both crucially influenced by the UPS. Recently, there have been several reports on DUBs involved in bone homeostasis and various bone disorders through the regulation of osteoblasts and osteoclasts via NF-κB, Wnt/ß-catenin, TRAF6, TGFß, ERK1/2, and PI3K/Akt pathways. However, DUBs regulating function in bone homeostasis is still in its infancy. Here, we summarized several recent identifications on DUBs, with a focus on their role in bone cancer progression. Therefore, the study attempts to summarize association with the expression level of DUBs as key factors driving bone cancers and also provide new insights on DUBs as key pharmacologic targets for bone cancer therapeutics.

MERTK Is a Potential Therapeutic Target in Ewing Sarcoma.

Outcomes are poor in patients with advanced or relapsed Ewing sarcoma (EWS) and current treatments have significant short- and long-term side effects. New, less toxic and more effective treatments are urgently needed. MER proto-oncogene tyrosine kinase (MERTK) promotes tumor cell survival, metastasis, and resistance to cytotoxic and targeted therapies in a variety of cancers. MERTK was ubiquitously expressed in five EWS cell lines and five patient samples. Moreover, data from CRISPR-based library screens indicated that EWS cell lines are particularly dependent on MERTK. Treatment with MRX-2843, a first-in-class, MERTK-selective tyrosine kinase inhibitor currently in clinical trials, decreased the phosphorylation of MERTK and downstream signaling in a dose-dependent manner in A673 and TC106 cells and provided potent anti-tumor activity against all five EWS cell lines, with IC50 values ranging from 178 to 297 nM. Inhibition of MERTK correlated with anti-tumor activity, suggesting MERTK inhibition as a therapeutic mechanism of MRX-2843. Combined treatment with MRX-2843 and BCL-2 inhibitors venetoclax or navitoclax provided enhanced therapeutic activity compared to single agents. These data highlight MERTK as a promising therapeutic target in EWS and provide rationale for the development of MRX-2843 for the treatment of EWS, especially in combination with BCL-2 inhibitors.

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.

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.