Ewing's Family Research Articles

Carboplatin and paclitaxel adjuvant chemotherapy in primitive neuroectodermal tumor of the uterine corpus

Primitive neuroectodermal tumor of the uterine corpus (PNET) is rare and appears to have an aggressive clinical course. We report on a postmenopausal woman with optimal surgically cytoreduced advanced-stage PNET in which adjuvant combination chemotherapy with platinum and taxane agents was unsuccessful in extending her disease-free survival.

Genetically defined EWS/FLI1 model system suggests mesenchymal origin of Ewing's family tumors

Ewing's family tumors (EFTs) are characterized by recurrent chromosomal translocations that produce chimeric fusions between the EWS gene and one of five ETS transcription factors. The expression of EWS/FLI1, the predominant fusion product in EFTs, is believed to deregulate downstream target genes in an undefined tissue type and leads to development of EFTs. Attempts to generate model systems that represent EFTs have been hampered by an unexpected toxicity of the fusion gene. In the present study, we used gene expression analysis to identify tissue types based on the similarity of their expression profiles to those of EWS/FLI1-modulated genes. The data obtained from this screen helped to identify IMR-90 cells, a human fetal fibroblast, that upon further manipulation can maintain stable EWS/FLI1 expression without the reported toxicity. In addition, gene expression profiling of these cells revealed a significant overlap of genes that have been previously reported to be targets of EWS/FLI1. Furthermore, we show, for the first time, a partial transformation of these human primary fibroblasts with EWS/FLI1 expression. The experiments presented here provide a solid foundation for generation of a new model system for studying Ewing's sarcoma biology.

Diagnostic and Prognostic Sarcoma Signatures

Sarcomas are a diverse group of childhood and adult tumors that arise from mesenchymal tissue. In contrast to epithelial tumors, most of which are defined by a specific organ system, sarcomas can arise virtually anywhere in the body, such that their characteristic histopathology and clinical presentation form the core diagnostic criteria.Precise identification by differential diagnosis is the first element of a successful treatment, since these tumors show wide variation in response to specific therapies and misdiagnosis can lead to suboptimal therapy. However, due to overlapping histopathologic features among the sarcomas, as well as the multiple subtypes or variants within a single histologic group, pathologists and clinicians are increasingly reliant on molecular diagnostic approaches to aid in the differential diagnosis. Gene expression profiling or microarray analysis is now being used to develop expression signatures that appear to be better than histological features or any single biomarker at discriminating tumor types, identifying clinical variants, and modeling complex tumor behavior.This review examines the current progress in identifying diagnostic and prognostic expression signatures for four sarcomas: rhabdomyosarcoma, Ewing's family of tumors, synovial sarcoma, and osteosarcoma. In this context, we discuss the current status and future potential for using expression signatures to improve tumor classification, outcome prediction, and therapeutic response in patients with these sarcomas.

Primary Extraskeletal Ewing Family Tumor With Complex Epithelial Differentiation: A Unique Case Arising in the Lateral Neck Presenting With Horner Syndrome

A great deal of attention has been given to epithelial differentiation in Ewing family of tumors (EFTs) in recent years, with studies showing variable keratin expression in 20% to 32% of cases. A 29-year-old man presented with a right-sided Horner syndrome suggesting a sympathetic chain related lesion. No radiologic evidence of a mass was appreciated initially. Several months later, he developed right vocal cord palsy and a large right-sided neck mass. An open biopsy demonstrated a high-grade malignant neoplasm with sheets of undifferentiated round cells infiltrating soft tissues and a large peripheral branch of the vagus nerve. Focally, the tumor abruptly produced keratinizing cells and frank squamous pearls. The tumor showed diffuse expression of CD99, high molecular weight keratin, p63, cytokeratin (CK) 5/6, AE1/AE3, CAM5.2, CK19, and focal CK14. It was negative for muscle-specific actin, desmin, MyoD1, MYF-4, S100, and CK7. Ultrastructurally, abundant cytoplasmic tonofilaments and well-formed desmosomes were demonstrated. Initial diagnosis was a metastatic squamous cell carcinoma of probable upper aerodigestive origin. Subsequently, the tumor was shown to harbor the t(11;22) involving EWSR1 and FLI-1 by reverse transcription-polymerase chain reaction, characteristic of EFT's, which was confirmed by dual color break apart fluorescence in-situ hybridization analysis. This tumor is related to, if not an example of the recently described "adamantinoma-like" EFT and demonstrates a potential diagnostic pitfall. It seems to be the first EFT to arise within, or in close proximity to the cervical sympathetic chain of ganglia. It is also the first EFT with complex epithelial differentiation arising outside the extremities and with diffuse expression of high molecular weight keratin and p63.

DAX1, a direct target of EWS/FLI1 oncoprotein, is a principal regulator of cell-cycle progression in Ewing's tumor cells

The molecular hallmark of the Ewing's family of tumors is the presence of balanced chromosomal translocations, leading to the formation of chimerical transcription factors (that is, EWS/FLI1) that play a pivotal role in the pathogenesis of Ewing's tumors by deregulating gene expression. We have recently demonstrated that DAX1 (NR0B1), an orphan nuclear receptor that was not previously implicated in cancer, is induced by the EWS/FLI1 oncoprotein and is highly expressed in Ewing's tumors, suggesting that DAX1 is a biologically relevant target of EWS/FLI1-mediated oncogenesis. In this study we demonstrate that DAX1 is a direct transcriptional target of the EWS/FLI1 oncoprotein through its binding to a GGAA-rich region in the DAX1 promoter and show that DAX1 is a key player of EWS/FLI1-mediated oncogenesis. DAX1 silencing using an inducible model of RNA interference induces growth arrest in the A673 Ewing's cell line and severely impairs its capability to grow in semisolid medium and form tumors in immunodeficient mice. Gene expression profile analysis demonstrated that about 10% of the genes regulated by EWS/FLI1 in Ewing's cells are DAX1 targets, confirming the importance of DAX1 in Ewing's oncogenesis. Functional genomic analysis, validated by quantitative RT-PCR, showed that genes implicated in cell-cycle progression, such as CDK2, CDC6, MCM10 or SKP2 were similarly regulated by EWS/FLI1 and DAX1. These findings indicate that DAX1 is important in the pathogenesis of the Ewing's family of tumors, identify new functions for DAX1 as a cell-cycle progression regulator and open the possibility to new therapeutic approaches based on DAX1 function interference.

High-dose therapy with hematopoietic stem cell rescue in patients with poor prognosis Ewing family tumors

The purpose of the study was to evaluate the feasibility and safety of two cycles of high-dose chemotherapy (HDT) followed by autologous hematopoietic SCT (HSCT) in patients with poor prognosis Ewing family of tumors (EFT). Twenty patients with primary metastatic bulky disease or recurrent EFT were enrolled to a treatment protocol with two cycles of HDT and HSCT. Patients tolerated well the first (n=20) and second (n=13) cycles, with limited and predictable toxicities. Only one (5%) TRM occurred during the second cycle. Myeloid engraftment occurred at the median of 11 days after both cycles. At 3 years, the overall and EFS were 45% (confidence interval; CI 0.22, 0.69) and 47% (CI 0.25, 0.70), respectively, for the entire group and 58% (CI 0.30, 0.86) for patients who completed two cycles. Dose intensification with two cycles of HDT and HSCT is feasible and safe, with low and acceptable treatment-related morbidity and mortality. Adding a second course of therapy does not impair engraftment. However, only 65% of the patients were able to proceed to the second cycle. Further studies are required to define the optimal mode of delivery of HDT and HSCT in treatment of advanced EFT.

Post‐operative radiotherapy for Ewing sarcoma: when, how and how much?

Postoperative radiotherapy in Ewing family of tumors has undergone continuous evolution over the last few decades to establish its role in the combined modality management of these tumors. The process of evolution is still far from over. This review analyzes the evidence from major multi-institutional prospective trials as well as large retrospective institutional series in Ewing tumors to determine the current standards and controversies in postoperative radiation. The indications of PORT, radiation dose-fractionation, timing, target volumes and treatment planning, as well as the late effects are reviewed. A summary of evidence based consensus is presented and unresolved aspects are discussed. Pediatr Blood Cancer 2008;51:575-580. (c) 2008 Wiley-Liss, Inc.

Inducible Expression of Chimeric EWS/ETS Proteins Confers Ewing's Family Tumor-Like Phenotypes to Human Mesenchymal Progenitor Cells

Inducible Expression of Chimeric EWS/ETS Proteins Confers Ewing's Family Tumor-Like Phenotypes to Human Mesenchymal Progenitor Cells

Radiation Treatment for Ewing Family of Tumors in Adults: The University of Florida Experience

To review the clinical characteristics and outcomes of adult patients with Ewing family of tumors treated with radiation at the University of Florida. Clinical features, treatment, and outcomes of 47 patients older than 18 years with Ewing family of tumors treated with combined radiation therapy and chemotherapy from 1970 to 2005 were retrospectively reviewed. Analysis was stratified by age older or younger than 30 years. Patients with metastatic disease at the time of diagnosis were excluded from the study. The 29 men and 18 women had a median age of 24 years. Thirty-three patients were 18-30 years old and 14 patients were older than 30 years. Median follow-up of living patients was 8.2 years. The 5-year overall survival rate for all patients was 43% (p = 0.8523). The 5-year local control rate for all patients was 75% (p = 0.9326). The 5-year rate of freedom from distant metastasis for all patients was 45% (p = 0.5471). There were no significant differences in 5-year overall survival, local control, and freedom from distant metastasis rates; patterns of distant failure; or toxicity profiles between older adult patients and younger adult patients. We found that the natural history and treatment outcomes of the Ewing family of tumors were consistently similar in adults (young and old) and children. Thus, aggressive combined modality approaches should be considered for adult patients.

Phase II trial of ixabepilone (BMS-247550) in children and young adults with refractory solid tumors: A report from the Children’s Oncology Group

10026 Background: The epothilone B analog ixabepilone (IXB) is a non-taxane microtubule-stabilizing agent with activity in adult solid tumors and in vivo activity - q 4 days (d) × 3- in pediatric tumor xenografts de novo resistant to paclitaxel. The maximum tolerated dose in adults and children was 6 and 8 mg/m2/d IV over 1 hour × 5 d q 21d, respectively, and the prominent dose-limiting toxicity (DLT) was neutropenia. Methods: We performed a phase II trial of IXB (8 mg/m2/d × 5d q21d) in taxane naïve children and young adults. Using a two-stage design (stage 1: 10 pts/stratum) we evaluated six independent strata: rhabdomyosarcoma, Ewing family tumors, neuroblastoma, Wilms tumor, osteosarcoma, and synovial sarcoma or malignant peripheral nerve sheath tumor. DLT was ≥ grade 3 IXB related non-hematologic toxicity, grade 4 thrombocytopenia, or grade 4 neutropenia for ≥5 d. Results: 61 eligible pts (64 pts total) (male 36/female 25) were enrolled. Median age (range) at entry was 13 yrs (3–36 yrs), 8 pts ≥ 21 yo, and the number of prior regimens was 2 (1–6). 59 pts were evaluable for toxicity and response. DLT developed in 10/59 pts (16× <12 yo; 18× ≥12 yo) during cycle 1: pain (n=3), neutropenia (n=5), and one each developed sensory neuropathy, anorexia, fatigue, thrombocytopenia, dehydration, and CNS hemorrhage. In subsequent cycles, 6 pts developed DLT: anorexia (n=3), neutropenia (n=2), and one each thrombocytopenia, pain, sensory neuropathy, febrile neutropenia, lipase, hypertension. 13 pts (22×) had ≥ grade 2 pain related to IXB. No partial or complete responses (RECIST) were observed. The median number of cycles was 2 (range 1–18). 7 pts received ≥ 3 cycles, with 2 having prolonged stable disease (Wilms tumor 18+ cycles, synovial sarcoma 8 cycles). Conclusions: IXB was well tolerated at 8 mg/m2/d in children and adults, but did not demonstrate significant clinical activity in the pediatric tumors evaluated. The pediatric xenograft model was thus not predictive of IXB activity in these heavily pre-treated patients. No significant financial relationships to disclose.

Membrane‐associated phospholipase A1 beta (LIPI) Is an Ewing tumour‐associated cancer/testis antigen

Cancer/testis antigens (CTA) represent a heterogeneous group of antigens expressed nearly exclusively in tumour cells and testis. Recently, we identified phospholipase A1 beta (a CTA also known as lipase member I, LIPI) as a gene with high expression in Ewing family tumours (EFT). In the present paper we analyzed expression of LIPI in a panel of normal tissues and tumour samples. The expression of CTA in EFT and normal tissues was analyzed by using DNA microarray datasets. Expression of LIPI in EFT, a panel of other tumour samples, and normal tissues was analyzed by using RT-PCR and quantitative RT-PCR. LIPI was expressed in EFT samples but not in other investigated tumour samples. Expression of LIPI in normal tissues was restricted to testis and thyroid. However, expression in these tissues was low compared with EFT. Interestingly testis as well as thyroid expressed all analyzed EFT-associated transcripts, suggesting that these tissues harbour a small cell population with molecular features of EFT. The sensitivity of the LIPI RT-PCR was similar to the sensitivity of the conventional EWSR1-FLI1 RT-PCR, suggesting that LIPI might be useful as additional diagnostic target structure. The human cancer/testis antigen LIPI is highly expressed in Ewing family tumours and can be easily detected by RT-PCR or quantitative RT-PCR. LIPI might be an interesting target for the development of future diagnostic tools or treatment strategies.

Inducible Expression of Chimeric EWS/ETS Proteins Confers Ewing's Family Tumor-Like Phenotypes to Human Mesenchymal Progenitor Cells

Ewing's family tumor (EFT) is a rare pediatric tumor of unclear origin that occurs in bone and soft tissue. Specific chromosomal translocations found in EFT cause EWS to fuse to a subset of ets transcription factor genes (ETS), generating chimeric EWS/ETS proteins. These proteins are believed to play a crucial role in the onset and progression of EFT. However, the mechanisms responsible for the EWS/ETS-mediated onset remain unclear. Here we report the establishment of a tetracycline-controlled EWS/ETS-inducible system in human bone marrow-derived mesenchymal progenitor cells (MPCs). Ectopic expression of both EWS/FLI1 and EWS/ERG proteins resulted in a dramatic change of morphology, i.e., from a mesenchymal spindle shape to a small round-to-polygonal cell, one of the characteristics of EFT. EWS/ETS also induced immunophenotypic changes in MPCs, including the disappearance of the mesenchyme-positive markers CD10 and CD13 and the up-regulation of the EFT-positive markers CD54, CD99, CD117, and CD271. Furthermore, a prominent shift from the gene expression profile of MPCs to that of EFT was observed in the presence of EWS/ETS. Together with the observation that EWS/ETS enhances the ability of cells to invade Matrigel, these results suggest that EWS/ETS proteins contribute to alterations of cellular features and confer an EFT-like phenotype to human MPCs.

EWS/FLI1 suppresses retinoblastoma protein function and senescence in Ewing's sarcoma cells

Ewing's Family Tumors (EFTs) most commonly harbor a specific t(11;22) translocation that generates the EWS/FLI1 fusion protein responsible for malignant transformation. Many potential downstream targets of EWS/FLI1 have been identified but a detailed mechanism by which the fusion protein brings about transformation remains unknown. In this report, we show that depletion of EWS/FLI1 in Ewing's cell lines results in a senescence phenotype, a marked increase in expression of the G1/S regulatory proteins p27(kip1) and p57(kip2), and a significant decrease in cyclin D1 and CDK2. We also demonstrate for the first time, to our knowledge, that knockdown of EWS/FLI1 leads to hypophosphorylation and functional activation of the retinoblastoma (pRb) family of proteins. Consistent with activation of the pRb proteins, E2F-responsive genes such as cyclin A are repressed in EWS/FLI1-depleted cells. Together, these results support the role of EWS/LI1 as an inhibitor of cellular senescence and implicate the retinoblastoma family of proteins as key mediators of this inhibition.

Primitive Neuroectodermal Tumor of the Kidney: A Single Institute Series of 16 Patients

Primitive neuroectodermal tumor (PNET) of the kidney is a rare entity, the diagnosis usually being made at histopathology. Few cases reported in literature revealed a variable presentation and an aggressive behavior. The purpose of our study was to review our experience in diagnosis and the management of patients with renal PNET. The records of 16 patients of renal PNET treated between 1995 and 2003 were reviewed retrospectively and our data compared with the literature. There were 10 male and 6 female patients with median age of 27 years. At presentation, 10 patients (63%) had localized disease, 5 (31%) had metastatic disease and 1 (6%) had locally advanced disease. The presence of Homer-Wright type rosettes on hematoxylin and eosin staining and CD99 (cluster differentiation) products positivity on immunohistochemistry supported the diagnosis. Radical nephrectomy was performed in operable cases and all patients received chemotherapy. Nine patients received adjuvant radiotherapy to the renal bed. Median follow-up was 31 months (range 4 to 92). Overall median survival was 40 months with 3- and 5-year survival of 60% and 42%, respectively. The diagnosis of renal PNET must be considered in young patients presenting with renal mass. Standard therapy consists of combination of surgical resection, postoperative irradiation and chemotherapy. Chemotherapy regimen used is either RCT II (round cell tumor) protocol or EFT 2001 (Ewing's family of tumors) protocol. However, further studies are required to validate the appropriate chemotherapy protocol.

SK‐NEP‐1 and Rh1 are Ewing family tumor lines

The utility of preclinical models of childhood cancers is contingent upon reliably classifying them with their corresponding clinical counterparts. Molecular tools such as gene expression profiling allow researchers to confirm the similarity between clinical tumors and preclinical models. We describe the use of gene expression profiling to show that SK-NEP-1, a cell line previously thought to represent anaplastic Wilms tumor, is instead related to Ewing sarcoma. RT-PCR confirmed that SK-NEP-1 expresses EWS-FLI1 gene fusion transcripts characteristic of Ewing sarcoma, and DNA sequencing demonstrated the joining of exon 7 of EWS with exon 5 of FLI1 for these transcripts. Rh1, which was previously categorized as an alveolar rhabdomyosarcoma cell line, also has a gene expression profile suggestive of Ewing sarcoma and expresses EWS-FLI1 fusion transcripts in which exon 7 of EWS is joined with exon 6 of FLI1. These examples illustrate the importance of molecularly characterizing pediatric preclinical models used for testing new agents.

ASSESSMENT OF MUSCARINIC AND NICOTINIC ACETYLCHOLINE RECEPTOR EXPRESSION IN PRIMITIVE NEUROECTODERMAL TUMOR/EWING FAMILY OF TUMOR AND DESMOPLASTIC SMALL ROUND CELL TUMOR: AN IMMUNOHISTOCHEMICAL AND WESTERN BLOT STUDY OF TISSUE MICROARRAY AND CELL LINES

The primitive neuroectodermal tumor (PNET)/Ewing family of tumors (EFT) and desmoplastic small round cell tumor (DSRCT) portend a grave prognosis. Ongoing research in similar neurocrest-derived neoplasms has implicated both the muscarinic acetylcholine receptor (mAChR) and nicotinic acetylcholine receptor (nAChR) in the pathogenesis of these neoplasms. Acetylcholine has been reported to impart a modulatory effect on chemotaxis and proliferation, an effect ameliorated by anticholinergic drugs. The aim of our study is to characterize the pattern of expression of mAChR and nAChR in PNET/EFT and DSRCT, in hopes of discovering a potential target for therapeutic improvements. We examined 34 cases of PNET/EFT and 2 DSRCT retrospectively by immunohistochemical studies. We found that AChRs are overexpressed in a significant number of PNET/EFT and DSRCT. The Western blot analysis of 3 human Ewing sarcoma cell lines confirms the presence of AChRs. Future studies are planned to confirm these results as well as to investigate their potential therapeutic implications.

The EWS/FLI1 oncogenic transcription factor deregulates GLI1

Ewing family tumors (EFT), classically Ewing's sarcoma and peripheral primitive neuroectodermal tumor, share a common class of tumor-specific fusion genes thought to be key mediators of tumor biology. Here we demonstrate that the most common Ewing's fusion, EWS/FLI1, produces transcriptional upregulation of GLI1 and its direct transcriptional target PATCHED1 in a model transformation system. This deregulation of GLI1 is common to other EWS/ets chimera and depends on the functional transcriptional regulatory domains. Inhibition of GLI1 via RNAi or via overexpression of endogenous inhibitors results in a reduction of EWS/FLI1 transformation activity. Activation of GLI1 appears to occur in a Hedgehog-independent fashion as blockade of Hedgehog signaling has only a modest effect on EFT cells. We present evidence that EWS/FLI1 upregulation of cMYC may play a role in the upregulation of GLI1 in EWS/FLI1-transformed NIH3T3 cells. Finally, we demonstrate that observations made in a model transformation system translate to an Ewing cellular background. EFT cell lines express GLI1 and PATCHED and this expression is EWS/FLI1 dependent. Inhibition of GLI1 expression via RNAi results in reduced anchorage-independent growth in an EFT cell line. GLI1 appears to be a transcriptionally deregulated target of EWS/FLI1 that mediates a portion of its tumorigenic phenotype.

Novel Markers of Subclinical Disease for Ewing Family Tumors from Gene Expression Profiling

Targeting subclinical disease in the bone marrow is particularly relevant in metastatic Ewing family tumors (EFT) where cure is difficult. Genome-wide expression arrays can uncover novel genes differentially expressed in tumors over normal marrow/blood, which may have potentials as markers of subclinical disease. Gene expression array data were obtained on 28 EFT tumors using the Affymetrix U133 gene chip and compared with 10 normal blood samples. Ten genes with high tumor to blood ratios were identified. Quantitative reverse transcription-PCR was done to study (a) the dynamic range of detection of rare tumor cells, (b) the gene expression in normal blood/marrow samples, (c) the gene expression among EFT tumors, and (d) the detection and prognostic impact of marker positivity in histology-negative diagnostic marrows of EFT patients. Five of 10 genes (i.e., six-transmembrane epithelial antigen of the prostate 1 [STEAP1], cyclin D1 [CCND1], NKX2-2 transcription factor [NKX2-2], plakophilin 1 [PKP1], and transmembrane protein 47 [TMEM47]) were chosen for further analyses based on their steep linear dynamic range in detecting tumor cells seeded in normal mononuclear cells and on their homogeneous expression among EFT tumors. Prognostic effect was evaluated in 35 histology-negative diagnostic marrows. Marker negativity of STEAP1, CCND1, or NKX2-2, as well as three markers in combination, was strongly correlated with patient survival as well as survival without new metastases. This gene expression array-based approach identified novel markers that may be informative at diagnosis for risk group assessment. Their clinical utility needs to be tested in large patient cohorts.

The mechanism of cross-resistance to proteasome inhibitor bortezomib and overcoming resistance in Ewing's family tumor cells

EWS-Fli1 plays important roles in oncogenesis of Ewing's family tumors (EFTs). We have reported that EWS-Fli1 inhibits p21(waf1/cip1) and p27(kip1) expressions, which are degraded by the ubiquitin-proteasome pathway. Bortezomib efficiently up-regulated p21(waf1/cip1) and p27(kip1) expression, and induced apoptosis accompanied by the expression of cleaved-PARP, DR4 and activated caspase-8 in EFT cells. Since most EFTs deaths result from the tumor being resistant to chemotherapeutic drugs, the effects of novel anti-tumor reagents on drug-resistant tumors were next investigated. The results demonstrated that the drug-resistant EFT clones were cross-resistant to bortezomib probably due to the over-expression of the efflux pumps, P-glycoprotein and MRP1. We further investigated whether the efflux pump inhibitors would modulate the effects of bortezomib. The combination of P-gp-specific or MRP1-specific inhibitors could enhance the anti-tumor effects of bortezomib on the drug-resistant clones. These data suggest that bortezomib might be a substrate of P-gp and MRP1. Although bortezomib would be effective on the primary EFTs, it is necessary to pay attention to the resistance to bortezomib in clinical trials for the advanced cases. The combination of bortezomib and the efflux pump inhibitors might be a promising method as a novel molecular target therapy for advanced EFTs.

CD99 negative primary sciatic nerve Ewing family tumour in a middle-aged woman: a rare clinical presentation

CD99 negative primary sciatic nerve Ewing family tumour in a middle-aged woman: a rare clinical presentation