Outcomes of Patients Treated in the UK Proton Overseas Programme: Non-central Nervous System Group.

AIMS: The UK Proton Overseas Programme (POP) was launched in 2008. The Proton Clinical Outcomes Unit (PCOU) warehouses a centralised registry for collection, curation and analysis of all outcomes data for all National Health Service-funded UK patients referred and treated abroad with proton beam therapy (PBT) via the POP. Outcomes are reported and analysed here for patients diagnosed with non-central nervous system tumours treated from 2008 to September 2020 via the POP. MATERIALS AND METHODS: All non-central nervous system tumour files for treatments as of 30 September 2020 were interrogated for follow-up information, and type (following CTCAE v4) and time of onset of any late (>90 days post-PBT completion) grade 3-5 toxicities. RESULTS: Four hundred and ninety-five patients were analysed. The median follow-up was 2.1 years (0-9.3 years). The median age was 11 years (0-69 years). 70.3% of patients were paediatric (<16 years). Rhabdomyosarcoma (RMS) and Ewing sarcoma were the most common diagnoses (42.6% and 34.1%). 51.3% of treated patients were for head and neck (H&N) tumours. At last known follow-up, 86.1% of all patients were alive, with a 2-year survival rate of 88.3% and 2-year local control of 90.3%. Mortality and local control were worse for adults (≥25 years) than for the younger groups. The grade 3 toxicity rate was 12.6%, with a median onset of 2.3 years. Most were in the H&N region in paediatric patients with RMS. Cataracts (30.5%) were the most common, then musculoskeletal deformity (10.1%) and premature menopause (10.1%). Three paediatric patients (1-3 years at treatment) experienced secondary malignancy. Seven grade 4 toxicities occurred (1.6%), all in the H&N region and most in paediatric patients with RMS. Six related to eyes (cataracts, retinopathy, scleral disorder) or ears (hearing impairment). CONCLUSIONS: This study is the largest to date for RMS and Ewing sarcoma, undergoing multimodality therapy including PBT. It demonstrates good local control, survival and acceptable toxicity rates.

Comparison of two chemotherapy regimens in patients with newly diagnosed Ewing sarcoma (EE2012): an open-label, randomised, phase 3 trial.

BACKGROUND: Internationally, a single standard chemotherapy treatment for Ewing sarcoma is not defined. Because different chemotherapy regimens were standard in Europe and the USA for newly diagnosed Ewing sarcoma, and in the absence of novel agents to investigate, we aimed to compare these two strategies. METHODS: EURO EWING 2012 was a European investigator-initiated, open-label, randomised, controlled phase 3 trial done in 10 countries. We included patients aged 2-49 years, with any histologically and genetically confirmed Ewing sarcoma of bone or soft tissue, or Ewing-like sarcomas. The eligibility criteria originally excluded patients with extrapulmonary metastatic disease, but this was amended in the protocol (version 3.0) in September, 2016. Patients were randomly assigned (1:1) to either the European regimen of vincristine, ifosfamide, doxorubicin, and etoposide induction, and consolidation using vincristine, actinomycin D, with ifosfamide or cyclophosphamide, or busulfan and melphalan (group 1); or the US regimen of vincristine, doxorubicin, cyclophosphamide, ifosfamide, and etoposide induction, plus ifosfamide and etoposide, and consolidation using vincristine and cyclophosphamide, or vincristine, actinomycin D, and ifosfamide, with busulfan and melphalan (group 2). All drugs were administered intravenously. The primary outcome measure was event-free survival. We used a Bayesian approach for the design, analysis, and interpretation of the results. Patients who received at least one dose of study treatment were considered in the safety analysis. The trial was registered with EudraCT, 2012-002107-17, and ISRCTN, 54540667. FINDINGS: Between March 21, 2014, and May 1, 2019, 640 patients were entered into EE2012, 320 (50%) randomly allocated to each group. Median follow-up of surviving patients was 47 months (range 0-84). Event-free survival at 3 years was 61% with group 1 and 67% with group 2 (adjusted hazard ratio [HR] 0·71 [95% credible interval 0·55-0·92 in favour of group 1). The probability that the true HR was less than 1·0 was greater than 0·99. Febrile neutropenia as a grade 3-5 treatment toxicity occurred in 234 (74%) patients in group 1 and in 183 (58%) patients in group 2. More patients in group 1 (n=205 [64%]) required at least one platelet transfusion compared with those in group 2 (n=138 [43%]). Conversely, more patients required blood transfusions in group 2 (n=286 [89%]) than in group 1 (n=277 [87%]). INTERPRETATION: Dose-intensive chemotherapy with vincristine, doxorubicin, cyclophosphamide, ifosfamide, and etoposide is more effective, less toxic, and shorter in duration for all stages of newly diagnosed Ewing sarcoma than vincristine, ifosfamide, doxorubicin, and etoposide induction and should now be the standard of care for Ewing sarcoma. FUNDING: The European Union's Seventh Framework Programme for Research, Technological Development, and Demonstration; The National Coordinating Centre in France, Centre Léon Bérard; SFCE; Ligue contre le cancer; Cancer Research UK.

Analysis of stem cell collections in adult patients with Ewing sarcoma.

BACKGROUND: Ewing sarcoma is one of the most frequent soft-tissue tumors in pediatric patients. The current treatment protocols recommend stem cell apheresis (SCA) after completion of the second course of induction therapy with vincristine, ifosfamide, doxorubicine, and etoposide (VIDE). The feasibility of SCA and graft compositions in adult patients with Ewing sarcoma have not been previously analyzed. METHODS AND MATERIALS: The authors analyzed 29 stem cell collections of 19 adult patients (9 male, 10 female) at a median age of 27 (range 19-53) years mobilized after VIDE (n = 17), cyclophosphamide/topotecan (n = 1) or vincristine, dactinomycin and ifosfamide (n = 1) chemotherapy. All patients were mobilized with filgrastim 5 µg/kg twice daily from day +7 of chemotherapy. The collections were performed if CD34+ cell count in peripheral blood was >10/µL. The target yields were ≥4×106 CD34+ cells/kg body weight. RESULTS: Median CD34+ cells/µL in peripheral blood before SCA were 45.8 (range 6.7-614.4)/µL. The median cumulative yields were 10.6 (range 1.5-38.8) CD34+ cells/kg body weight and ≥2×106 in all but two patients (89%). CD34, CD3, and CD56 yields in collections after the third VIDE and after later courses did not differ. Four patients underwent high-dose therapy with autologous transplantation, and all were engrafted. DISCUSSION: Stem cell mobilization is feasible in most Ewing sarcoma patients. Additionally, the present study's data suggest that it is safe to postpone stem cell collection to a later VIDE chemotherapy cycle if medically indicated.

Unraveling Ewing Sarcoma Tumorigenesis Originating from Patient-Derived Mesenchymal Stem Cells.

Ewing sarcoma is characterized by pathognomonic translocations, most frequently fusing EWSR1 with FLI1. An estimated 30% of Ewing sarcoma tumors also display genetic alterations in STAG2, TP53, or CDKN2A (SPC). Numerous attempts to develop relevant Ewing sarcoma models from primary human cells have been unsuccessful in faithfully recapitulating the phenotypic, transcriptomic, and epigenetic features of Ewing sarcoma. In this study, by engineering the t(11;22)(q24;q12) translocation together with a combination of SPC mutations, we generated a wide collection of immortalized cells (EWIma cells) tolerating EWSR1-FLI1 expression from primary mesenchymal stem cells (MSC) derived from a patient with Ewing sarcoma. Within this model, SPC alterations strongly favored Ewing sarcoma oncogenicity. Xenograft experiments with independent EWIma cells induced tumors and metastases in mice, which displayed bona fide features of Ewing sarcoma. EWIma cells presented balanced but also more complex translocation profiles mimicking chromoplexy, which is frequently observed in Ewing sarcoma and other cancers. Collectively, these results demonstrate that bone marrow-derived MSCs are a source of origin for Ewing sarcoma and also provide original experimental models to investigate Ewing sarcomagenesis. SIGNIFICANCE: These findings demonstrate that Ewing sarcoma can originate from human bone-marrow-derived mesenchymal stem cells and that recurrent mutations support EWSR1-FLI1 translocation-mediated transformation.

Molecular Approaches to Diagnosis in Ewing Sarcoma: Fluorescence In Situ Hybridization (FISH).

The differential diagnosis of small round cell tumors (SRCT) crucially relies on the synoptic evaluation of morphology, immunohistochemical patterns, and molecular features. Though the implementation of broad RNA sequencing in diagnostic molecular pathology routines has substantially changed the standards of molecular affirmation of diagnoses, fluorescence in situ hybridization (FISH) on formalin-fixed, paraffin-embedded (FFPE) tissue sections is still an elementary tool to provide a rapid molecular corroboration of diagnoses, essentially required for therapeutic decisions. We discuss here the major FISH approaches currently employed in diagnostic molecular pathology, addressing classic Ewing sarcoma and differential diagnoses among SRCT which cannot sufficiently be ruled out by immunohistochemistry. This chapter will approach technical issues but particularly strategies and pitfalls in the interpretation of FISH patterns.

Main Repositories and Databases Used in Ewing Sarcoma Research.

Within sarcomas 50 different histological subtypes exist, each with their own molecular and clinical characteristics. The combination of tumor subtype heterogeneity and often a limited number of clinical cases make detailed molecular sarcoma studies challenging, particularly when focusing on individual cohorts. However, the increasing number of publicly available genomics data opens inroads to overcome this obstacle. The international public repositories for high-throughput microarray and next-generation sequence functional genomic data sets submitted by the research community create resources that are freely available for download in a variety of formats. Here, we describe the selected web resources for sarcoma genomics research. These resources support archiving of raw data, processed data, and metadata which are indexed, cross-linked, and searchable.

Systems Biology Analysis for Ewing Sarcoma.

Ewing sarcoma (EwS) is a highly aggressive pediatric bone cancer that is defined by a somatic fusion between the EWSR1 gene and an ETS family member, most frequently the FLI1 gene, leading to expression of a chimeric transcription factor EWSR1-FLI1. Otherwise, EwS is one of the most genetically stable cancers. The situation when the major cancer driver is well known looks like a unique opportunity for applying the systems biology approach in order to understand the EwS mechanisms as well as to uncover some general mechanistic principles of carcinogenesis. A number of studies have been performed revealing the direct and indirect effects of EWSR1-FLI1 on multiple aspects of cellular life. Nevertheless, the emerging picture of the oncogene action appears to be highly complex and systemic, with multiple reciprocal influences between the immediate consequences of the driver mutation and intracellular and intercellular molecular mechanisms, including regulation of transcription, epigenome, and tumoral microenvironment. In this chapter, we present an overview of existing molecular profiling resources available for EwS tumors and cell lines and provide an online comprehensive catalogue of publicly available omics and other datasets. We further highlight the systems biology studies of EwS, involving mathematical modeling of networks and integration of molecular data. We conclude that despite the seeming simplicity, a lot has yet to be understood on the systems-wide mechanisms connecting the driver mutation and the major cellular phenotypes of this pediatric cancer. Overall, this chapter can serve as a guide for a systems biology researcher to start working on EwS.

Case-control study of paternal occupational exposures and childhood bone tumours and soft-tissue sarcomas in Great Britain, 1962-2010.

BACKGROUND: This nationwide study investigated associations between paternal occupational exposure and childhood bone tumours and soft- tissue sarcomas. METHODS: The UK National Registry of Childhood Tumours provided cases of childhood sarcomas born and diagnosed in Great Britain, 1962-2010. Control births, unaffected by childhood cancer, were matched on sex, birth period and birth registration sub-district. Fathers' occupations were assigned to one or more of 33 exposure groups and coded for occupational social class. RESULTS: We analysed 5,369 childhood sarcoma cases and 5380 controls. Total bone tumours, total soft-tissue sarcomas and the subgroups osteosarcoma, rhabdomyosarcoma and Ewing Sarcoma Family of Tumours (ESFT) were considered separately. Significant positive associations were seen between rhabdomyosarcoma and paternal exposure to EMFs (odds ratio = 1.67, CI = 1.22-2.28) and also for ESFT and textile dust (1.93, 1.01-3.63). There were putative protective effects on total bone tumours of paternal dermal exposure to hydrocarbons, metal, metal working or oil mists. CONCLUSIONS: Despite the large size and freedom from bias of this study, our results should be interpreted with caution. Many significance tests were undertaken, and chance findings are to be expected. Nevertheless, our finding of associations between ESFT and paternal exposure to textile dust may support related suggestions in the literature.

Loss of Stag2 cooperates with EWS-FLI1 to transform murine Mesenchymal stem cells.

BACKGROUND: Ewing sarcoma is a malignancy of primitive cells, possibly of mesenchymal origin. It is probable that genetic perturbations other than EWS-FLI1 cooperate with it to produce the tumor. Sequencing studies identified STAG2 mutations in approximately 15% of cases in humans. In the present study, we hypothesize that loss of Stag2 cooperates with EWS-FLI1 in generating sarcomas derived from murine mesenchymal stem cells (MSCs). METHODS: Mice bearing an inducible EWS-FLI1 transgene were crossed to p53-/- mice in pure C57/Bl6 background. MSCs were derived from the bone marrow of the mice. EWS-FLI1 induction and Stag2 knockdown were achieved in vitro by adenovirus-Cre and shRNA-bearing pGIPZ lentiviral infection, respectively. The cells were then treated with ionizing radiation to 10 Gy. Anchorage independent growth in vitro was assessed by soft agar assays. Cellular migration and invasion were evaluated by transwell assays. Cells were injected with Matrigel intramuscularly into C57/Bl6 mice to test for tumor formation. RESULTS: Primary murine MSCs with the genotype EWS-FLI1 p53-/- were resistant to transformation and did not form tumors in syngeneic mice without irradiation. Stag2 inhibition increased the efficiency and speed of sarcoma formation significantly in irradiated EWS-FLI1 p53-/- MSCs. The efficiency of tumor formation was 91% for cells in mice injected with Stag2-repressed cells and 22% for mice receiving cells without Stag2 inhibition (p < .001). Stag2 knockdown reduced survival of mice in Kaplan-Meier analysis (p < .001). It also increased MSC migration and invasion in vitro but did not affect proliferation rate or aneuploidy. CONCLUSION: Loss of Stag2 has a synergistic effect with EWS-FLI1 in the production of sarcomas from murine MSCs, but the mechanism may not relate to increased proliferation or chromosomal instability. Primary murine MSCs are resistant to transformation, and the combination of p53 null mutation, EWS-FLI1, and Stag2 inhibition does not confer immediate conversion of MSCs to sarcomas. Irradiation is necessary in this model, suggesting that perturbations of other genes beside Stag2 and p53 are likely to be essential in the development of EWS-FLI1-driven sarcomas from MSCs.

Microenvironmental Factors Drive Tenascin C and Src Cooperation to Promote Invadopodia Formation in Ewing Sarcoma.

Ewing sarcoma is a bone tumor most commonly diagnosed in adolescents and young adults. Survival for patients with recurrent or metastatic Ewing sarcoma is dismal and there is a dire need to better understand the mechanisms of cell metastasis specific to this disease. Our recent work demonstrated that microenvironmental stress leads to increased Ewing sarcoma cell invasion through Src activation. Additionally, we have shown that the matricellular protein tenascin C (TNC) promotes metastasis in Ewing sarcoma. A major role of both TNC and Src is mediation of cell-cell and cell-matrix interactions resulting in changes in cell motility, invasion, and adhesion. However, it remains largely unknown, if and how, TNC and Src are linked in these processes. We hypothesized that TNC is a positive regulator of invadopodia formation in Ewing sarcoma through its ability to activate Src. We demonstrate here that both tumor cell endogenous and exogenous TNC can enhance Src activation and invadopodia formation in Ewing sarcoma. We found that microenvironmental stress upregulates TNC expression and this is dampened with application of the Src inhibitor dasatinib, suggesting that TNC expression and Src activation cooperate to promote the invasive phenotype. This work reports the impact of stress-induced TNC expression on enhancing cell invadopodia formation, provides evidence for a feed forward loop between TNC and Src to promote cell metastatic behavior, and highlights a pathway by which microenvironment-driven TNC expression could be therapeutically targeted in Ewing sarcoma.

A 3-year study of atorvastatin in children and adolescents with heterozygous familial hypercholesterolemia.

BACKGROUND: The efficacy and safety of atorvastatin in children/adolescents aged 10-17 years with heterozygous familial hypercholesterolemia (HeFH) have been demonstrated in trials of up to 1 year in duration. However, the efficacy/safety of >1 year use of atorvastatin in children/adolescents with HeFH, including children from 6 years of age, has not been assessed. OBJECTIVE: To characterize the efficacy and safety of atorvastatin over 3 years and to assess the impact on growth and development in children aged 6-15 years with HeFH. METHODS: A total of 272 subjects aged 6-15 years with HeFH and low-density lipoprotein cholesterol (LDL-C) ≥4.0 mmol/L (154 mg/dL) were enrolled in a 3-year study (NCT00827606). Subjects were initiated on atorvastatin (5 mg or 10 mg) with doses increased to up to 80 mg based on LDL-C levels. RESULTS: Mean percentage reductions from baseline in LDL-C at 36 months/early termination were 43.8% for subjects at Tanner stage (TS) 1 and 39.9% for TS ≥2. There was no evidence of variations in the lipid-lowering efficacy of atorvastatin between the TS groups analyzed (1 vs ≥2) or in subjects aged <10 vs ≥10 years, and the treatment had no adverse effect on growth or maturation. Atorvastatin had a favorable safety and tolerability profile, and only 6 (2.2%) subjects discontinued because of adverse events. CONCLUSIONS: Atorvastatin over 3 years was efficacious, had no impact on growth/maturation, and was well tolerated in children and adolescents with HeFH aged 6-15 years.

Association of Cytotoxic T-lymphocyte Antigen-4 Polymorphisms with Malignant Bone Tumor Risk: A Meta-analysis.

BACKGROUND: Previous studies have assessed the association between the Cytotoxic T-lymphocyte Antigen- 4(CTLA-4) polymorphism with the risk of malignant bone tumor, but the conclusions were inconsistent. We aimed to clarify association of cytotoxic T-lymphocyte antigen-4 polymorphisms with malignant bone tumors risk by performing a meta-analysis. MATERIALS AND METHODS: The databases including PubMed, EMBase databases and the Cochrane Library were searched to identify the eligible studies prior to January 30 2016. Odds ratio (OR) with 95% confidence interval (95%CI) were used to estimate the strengths of the association between the CTLA-4 polymorphism and the malignant bone tumor risks. The meta-analysis was performed by STATA 12.0. RESULTS: Four individual studies with a total of 1003 cases with malignant bone tumors and 1162 controls were included in our meta-analysis. The results of meta-analysis on those data demonstrated that CTLA-4 +49G>A polymorphism was associated with the risk of Ewing's sarcoma and osteosarcoma strongly (A vs. G: : OR=1.36, 95%CI:1.20-1.54, p=0.000; AA+AG vs. GG: OR=1.35, 95%CI:1.14-1.61, p=0.001; AA vs. GG: OR=2.24, 95%CI:1.67-2.99, p=0.000; AA vs. AG+GG: OR=2.00, 95%CI:1.53-2.62, p=0.000), but CTLA-4 -318C/T polymorphism was not associated with the risk of malignant bone tumor (C vs. T: OR=0.76, 95%CI:0.76-1.08, p= 0.262; CC+CT vs. TT: OR=0.70, 95%CI:0.41-1.20, p=0.198; CC vs. TT: OR=0.69, 95%CI:0.40-1.19, p= 0.183; CC vs. CT+TT: OR=0.92, 95%CI:0.75-1.13, p= 0.419). Subgroup analysis showed that there are significantly positive correlations between CTLA-4 +49G>A polymorphism and increased risks of malignant bone tumors in large size of sample (A vs. G: OR=1.347, 95%CI: 1.172,1.548, p=0.000; AA vs. GG: OR=2.228, 95%CI: 1.608,3.085, p=0.000), Ewing's Sarcoma or Osteosarcoma (A vs. G: OR=1.361, 95%CI: 1.201,1.540, p=0.000; AA vs. GG: OR=2.236, 95%CI: 1.674,2.986, p=0.000), and PCR-RFLP or Sequencing(A vs. G: OR=1.361, 95%CI: 1.201,1.540, p=0.000; AA vs. GG: OR=2.236, 95%CI: 1.674,2.986, p=0.000), but CTLA-4 -318C/T polymorphism was not associated with the risk of malignant bone tumors in diagnosis, genotype method, and sample size (all p>0.05). CONCLUSIONS: CTLA-4 +49A/G variant was associated with an increased risk of developing the malignant bone tumors, such as Ewing's sarcoma and osteosarcoma. However, it failed to show any association between CTLA-4 -318C/T polymorphism and the risk of malignant bone tumors. Future large-scale studies remain to be done to confirm our conclusions.

TRAIL delivered by mesenchymal stromal/stem cells counteracts tumor development in orthotopic Ewing sarcoma models.

Ewing sarcoma (EWS) is the second most frequent pediatric malignant bone tumor. EWS patients have not seen any major therapeutic progress in the last 30 years, in particular in the case of metastatic disease, which requires new therapeutic strategies. The pro-apoptotic cytokine TNF-Related Apoptosis Inducing Ligand (TRAIL) can selectively kill tumor cells while sparing normal cells, making it a promising therapeutic tool in several types of cancer. However, certain EWS cell lines appear resistant to recombinant human (rh) TRAIL-induced apoptosis. We therefore hypothesized that a TRAIL presentation at the surface of the carrier cells might overcome this resistance and trigger apoptosis. For this purpose, human adipose mesenchymal stromal/stem cells (MSC) transfected in a stable manner to express full-length human TRAIL were co-cultured with several human EWS cell lines, inducing apoptosis by cell-to-cell contact even in cell lines initially resistant to rhTRAIL or AMG655, an antibody agonist to the death receptor, DR5. In vivo, TRAIL delivered by MSCs was able to counteract tumor progression in two orthotopic models of Ewing sarcoma, associated with caspase activation, indicating that a cell-based delivery of a potent apoptosis-inducing factor could be relevant in EWS.

Pediatric Malignant Bone Tumors: A Review and Update on Current Challenges, and Emerging Drug Targets.

Osteosarcoma (OS) and the Ewing sarcoma family of tumors (ESFT) are the most common malignant bone tumors in children and adolescents. While significant improvements in survival have been seen in other pediatric malignancies the treatment and prognosis for pediatric bone tumors has remained unchanged for the past 3 decades. This review and update of pediatric malignant bone tumors will provide a general overview of osteosarcoma and the Ewing sarcoma family of tumors, discuss bone tumor genomics, current challenges, and emerging drug targets.

The genomic landscape of the Ewing Sarcoma family of tumors reveals recurrent STAG2 mutation.

The Ewing sarcoma family of tumors (EFT) is a group of highly malignant small round blue cell tumors occurring in children and young adults. We report here the largest genomic survey to date of 101 EFT (65 tumors and 36 cell lines). Using a combination of whole genome sequencing and targeted sequencing approaches, we discover that EFT has a very low mutational burden (0.15 mutations/Mb) but frequent deleterious mutations in the cohesin complex subunit STAG2 (21.5% tumors, 44.4% cell lines), homozygous deletion of CDKN2A (13.8% and 50%) and mutations of TP53 (6.2% and 71.9%). We additionally note an increased prevalence of the BRCA2 K3326X polymorphism in EFT patient samples (7.3%) compared to population data (OR 7.1, p = 0.006). Using whole transcriptome sequencing, we find that 11% of tumors pathologically diagnosed as EFT lack a typical EWSR1 fusion oncogene and that these tumors do not have a characteristic Ewing sarcoma gene expression signature. We identify samples harboring novel fusion genes including FUS-NCATc2 and CIC-FOXO4 that may represent distinct small round blue cell tumor variants. In an independent EFT tissue microarray cohort, we show that STAG2 loss as detected by immunohistochemistry may be associated with more advanced disease (p = 0.15) and a modest decrease in overall survival (p = 0.10). These results significantly advance our understanding of the genomic and molecular underpinnings of Ewing sarcoma and provide a foundation towards further efforts to improve diagnosis, prognosis, and precision therapeutics testing.

Ewing's sarcoma precursors are highly enriched in embryonic osteochondrogenic progenitors.

Ewing's sarcoma is a highly malignant bone tumor found in children and adolescents, and the origin of this malignancy is not well understood. Here, we introduced a Ewing's sarcoma-associated genetic fusion of the genes encoding the RNA-binding protein EWS and the transcription factor ETS (EWS-ETS) into a fraction of cells enriched for osteochondrogenic progenitors derived from the embryonic superficial zone (eSZ) of long bones collected from late gestational murine embryos. EWS-ETS fusions efficiently induced Ewing's sarcoma-like small round cell sarcoma formation by these cells. Analysis of the eSZ revealed a fraction of a precursor cells that express growth/differentiation factor 5 (Gdf5), the transcription factor Erg, and parathyroid hormone-like hormone (Pthlh), and selection of the Pthlh-positive fraction alone further enhanced EWS-ETS-dependent tumor induction. Genes downstream of the EWS-ETS fusion protein were quite transcriptionally active in eSZ cells, especially in regions in which the chromatin structure of the ETS-responsive locus was open. Inhibition of ß-catenin, poly (ADP-ribose) polymerase 1 (PARP1), or enhancer of zeste homolog 2 (EZH2) suppressed cell growth in a murine model of Ewing's sarcoma, suggesting the utility of the current system as a preclinical model. These results indicate that eSZ cells are highly enriched in precursors to Ewing's sarcoma and provide clues to the histogenesis of Ewing's sarcoma in bone.

Is fluoride a risk factor for bone cancer? Small area analysis of osteosarcoma and Ewing sarcoma diagnosed among 0-49-year-olds in Great Britain, 1980-2005.

BACKGROUND: Artificial fluoridation of drinking water to improve dental health has long been a topic of controversy. Opponents of this public health measure have cited the possibility of bone cancer induction. The study objective was to examine whether increased risk of primary bone cancer was associated with living in areas with higher concentrations of fluoride in drinking water. METHODS: Case data on osteosarcoma and Ewing sarcoma, diagnosed at ages 0-49 years in Great Britain (GB) (defined here as England, Scotland and Wales) during the period 1980-2005, were obtained from population-based cancer registries. Data on fluoride levels in drinking water in England and Wales were accessed through regional water companies and the Drinking Water Inspectorate. Scottish Water provided data for Scotland. Negative binomial regression was used to examine the relationship between incidence rates and level of fluoride in drinking water at small area level. RESULTS: The study analysed 2566 osteosarcoma and 1650 Ewing sarcoma cases. There was no evidence of an association between osteosarcoma risk and fluoride in drinking water [relative risk (RR) per one part per million increase in the level of fluoride = 1·001; 90% confidence interval (CI) 0·871, 1·151] and similarly there was no association for Ewing sarcoma (RR = 0·929; 90% CI 0·773, 1·115). CONCLUSIONS: The findings from this study provide no evidence that higher levels of fluoride (whether natural or artificial) in drinking water in GB lead to greater risk of either osteosarcoma or Ewing sarcoma.

Update in treatment and targets in Ewing sarcoma.

The improvement in outcome for patients with localized and metastatic Ewing sarcoma since the development of cytotoxic chemotherapy remains one of the most profound advances in oncology and one of the proudest achievements of sarcoma researchers. Identification of molecular targets for new treatments has become an intense area within Ewing sarcoma research. The development of improved preclinical Ewing sarcoma models and advanced molecular techniques will build on knowledge of EWS/FLI1 function, EWS/FLI1 transcription targets, and the other critical driver events in these tumors.

Ewing sarcoma arising after treatment of diffuse large B-cell lymphoma.

We report the case of a patient in whom the diagnosis of Ewing sarcoma arising from a soft tissue was made after successful treatment of diffuse large B-cell lymphoma. A 65-year-old woman presented with a rapidly growing mass in her left scapular region 8 years after successful chemotherapy with the cyclophosphamide, hydroxydaunomycin hydrochloride, vincristine, prednisolone regimen for diffuse large B-cell lymphoma. Computed tomographic examination and magnetic resonance imaging of the thorax revealed an intramuscular tumour measuring 40 mm in size in the left scapular region. Histopathological examination of an open biopsy specimen revealed a small round cell tumour that showed positive staining for CD99. Fluorescence in situ hybridization showed a split signal by a break-apart probe for the EWS gene in chromosome 22q12. Reverse transcriptase-polymerase chain reaction confirmed the expression of EWS-FLI1 fusion transcripts. Based on these findings, the patient was diagnosed as having secondary Ewing sarcoma. Despite adjuvant chemotherapy, however, she died of pulmonary metastases 2 years after the diagnosis of Ewing sarcoma. Therapy-related haematological malignancies with balanced translocations have been reported previously. A mechanism similar to that underlying the development of secondary malignancy might explain the occurrence of this solid cancer.