Ewing's Family Research Articles

Abstract 2035: Anti-epileptic drug targets Ewing sarcoma.

Abstract Ewing sarcoma is a highly aggressive and metastatic bone or soft tissue tumor that affects children and adolescents. It is characterized by chromosomal translocations involving EWS gene and one of the ETS (Erythroblastosis virus E26 transformation-specific) families of transcription factors (ERG, FLI1, ETV1, ETV4, E1AF and FEV). All of the fusion genes juxtapose the EWS gene to an ETS related gene. Previously our laboratory has discovered several ETS oncogenes that have shown to play major roles in human cancers. ERG (ETS Related Gene), an important member of the ETS family genes, discovered by Drs. Reddy and Rao is shown to be involved in Ewing sarcoma. Our laboratory has previously demonstrated that ERG protein functions as a sequence specific transcriptional activator. Our preliminary results have shown that ERG and aberrant EWS-ERG proteins inhibit RXR transcriptional activation and apoptosis. These results suggest that transcriptional inhibition may play a major role in apoptosis function. Using a cell based assay system developed in our laboratory that measures the inhibitory activities of ERG proteins, we screened for known drugs that can reverse the inhibitory effects of RXR transcriptional activity. Since HDACs regulate nuclear receptors, we hypothesized that anti-epileptic drug, valproic acid and trichostatin-A (HDAC inhibitors) may reverse the inhibitory properties of EWS-ERG oncoprotein on RXR transcriptional activity and they can be used as therapeutic agents in Ewing sarcoma. Methods: Cell based assays were used to measure the RXR transcriptional activation function and in vivo assays were used to study the cell viability and apoptosis activity. Results: (1) Anti-epileptic drugs, valproic acid (VPA) and trichostatin-A (TSA) have shown to reverse the inhibitory effect of EWS-ERG on RXR transcriptional activity. (2) VPA and TSA inhibit the cell growth of Ewing sarcoma cells expressing EWS-ERG onco-protein. (3) VPA induce apoptosis in Ewing sarcoma cells. (4) VPA induce the expression of RXR target genes. Conclusion: Ewing sarcoma requires highly intensive chemotherapy along with surgery and/or radiation. Current therapies are associated with significant short and long term side effects. Hence new therapeutic approaches are needed. The above results suggest that the anti-epileptic drug VPA could be used as a potential treatment option for regulation of the function of EWS-ERG onco-protein. Thus, a promising drug with a new potential will have profound impact on prevention, management and treatment of Ewing family of cancers. Citation Format: Shubhalaxmi Kayarthodi, Yasuo Fujimura, Kunchala Rungsrisuriyachai, Jinbo Fang, Veena Rao, Shyam P. Reddy. Anti-epileptic drug targets Ewing sarcoma. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2035. doi:10.1158/1538-7445.AM2013-2035

Extraosseous Ewing Sarcoma and Peripheral Primitive Neuroectodermal Tumor of the Thyroid Gland: Case Report and Review

The Ewing family of tumors and peripheral primitive neuroectodermal tumor (pPNET) represent different manifestations of the same entity. Immunohistochemical and cytogenetic studies suggest that these tumors have a common origin. Ewing sarcoma is more common in bone, while pPNET is more common in soft tissues. Extraosseous Ewing sarcoma (EoES) is rare. We present the case of a 48-year-old man who presented with acute obstructive respiratory failure secondary to a large thyroid swelling. The patient was initially diagnosed with giant B-cell non-Hodgkin lymphoma and treated with chemotherapy. However, subsequent immunohistochemical staining of biopsy specimens revealed that the patient actually had EoES/pPNET of the thyroid gland. We performed a nearly complete surgical resection of the tumor plus a total laryngectomy and resection of five tracheal rings. However, the patient died of a cerebral metastasis 1 month later after he had completed one cycle of postoperative chemotherapy.

Extraosseous Ewing sarcoma of the vagina: a rare entity

Ewing sarcoma, a highly malignant neoplasm of the bone, usually occurs during childhood. About 15% are extraosseous. The Ewing family of tumors (EFTs) are extremely rare in the vagina. A 40-year literature review from 1970 to 2010 revealed only nine cases. A 32-year-old woman presented with a painless vaginal mass. A wide excision was performed. Histopathology, immunohistochemistry and molecular studies confirmed extraosseous vaginal Ewing sarcoma. Despite aggressive chemotherapy with a good initial response, she developed local recurrence and metastasis to the spine and pelvis and succumbed 22 months later. A previous infiltrating ductal breast cancer, treated and in remission complicated the picture. We present the tenth case of vaginal Ewing sarcoma and the fourth to be confirmed by molecular studies. We stress the importance of molecular techniques in definitely diagnosing EFTs, especially those arising at unusual sites, particularly in the context of a previous diagnosis of breast cancer.

Escalating Topotecan in Combination with Treosulfan has Acceptable Toxicity in Advanced Pediatric Sarcomas

Patients with advanced pediatric sarcomas have a poor prognosis and novel combination therapies are needed to improve the response rates. Hematological and organ related toxicities have been observed when administering topotecan in combination with, e.g., high dose thiotepa. This study evaluates the toxicity of escalating doses of topotecan alone or in combination with thiotepa or treosulfan. We compared the toxicity including death of complication (DOC) of topotecan alone or in combination with thiotepa or treosulfan in advanced pediatric sarcomas (n = 12). Ten of 12 patients (0.83) suffered from advanced tumors of the Ewing family (i.e., bone or marrow metastases or relapse <24 month after diagnosis, including one neuroepithelial tumor of the kidney) and two from alveolar rhabdomyosarcoma stage IV (0.17). Median age was 15 years (range 5–28). Ratio of female to male was 1:1. Two patients received topotecan alone (1.25 mg/m2 q 5d and 1.5 mg/m2 q 5d), three patients received four courses of topotecan (2 mg/m2 q d 1–5) in combination with thiotepa (100 mg/m2 q d 1–5), and seven patients received topotecan (2 mg/m2 q d 1–5) in combination with treosulfan (10g/m2 q d 3–5). Overall toxicity was not different between all three groups; mean scores were 1.6, 1.8, and 1.7 according to WHO grading (Scale 0–4). Organ related toxicity ranged between 0 and 4 and was not different as well. DOC was 0/2, 1/3, and 0/7 patients respectively. Escalating therapy with topotecan in combination with treosulfan has acceptable toxicity and warrants further investigation in advanced pediatric sarcomas.

Autologous stem cell transplantation in adults with metastatic sarcoma of the Ewing family: a single centre experience

Adults with metastatic Ewing family sarcomas (ES) after being treated with standard therapy for localised disease have limited treatment options with curative intent. The aim of this retrospective single centre study was to evaluate the efficacy of autologous stem cell transplantation (ASCT) in this patient population. We report on seven consecutive patients with ES. Four patients with initial localised disease developed distant metastases after being treated with initial standard pre-operative chemotherapy followed by surgery and subsequent standard post-operative chemotherapy. Three patients with initial metastatic disease were pre-treated with standard polychemotherapy. All patients received high-dose chemotherapy (HDCT) followed by ASCT for metastatic disease. For patients with initial metastatic disease, partial remission (PR) was achieved in three patients prior to HDCT. Type of response subsequent to ASCT was complete response (CR) in four patients with initial localised disease and CR in two patients with initial metastatic disease. No patient died within the first 100 days after HDCT. Side effects were rare and manageable. This retrospective analysis suggests that ASCT may be considered in patients with metastatic ES, previously treated with standard therapy.

FOXM1 Is an Oncogenic Mediator in Ewing Sarcoma

Ewing Family Tumors (Ewing Sarcoma and peripheral Primitive Neuroectodermal Tumor) are common bone and soft tissue malignancies of childhood, adolescence and young adulthood. Chromosomal translocation in these tumors produces fusion oncogenes of the EWS/ETS class, with EWS/FLI1 being by far the most common. EWS/ETS chimera are the only well established driver mutations in these tumors and they function as aberrant transcription factors. Understanding the downstream genes whose expression is modified has been a central approach to the study of these tumors. FOXM1 is a proliferation associated transcription factor which has increasingly been found to play a role in the pathogenesis of a wide range of human cancers. Here we demonstrate that FOXM1 is expressed in Ewing primary tumors and cell lines. Reduction in FOXM1 expression in Ewing cell lines results in diminished potential for anchorage independent growth. FOXM1 expression is enhanced by EWS/FLI1, though, unlike other tumor systems, it is not driven by expression of the EWS/FLI1 target GLI1. Thiostrepton is a compound known to inhibit FOXM1 by direct binding. We show that Thiostrepton diminishes FOXM1 expression in Ewing cell lines and this reduction reduces cell viability through an apoptotic mechanism. FOXM1 is involved in Ewing tumor pathogenesis and may prove to be a useful therapeutic target in Ewing tumors.

Characterization of Ewing sarcoma associated cancer/testis antigens

The prognosis of patients suffering from tumors of the Ewing family (EFT) is still poor. Immunotherapy strategies are pursued and EFT-specific antigens have to be identified as targets for cytotoxic T-lymphocytes (CTL). Due to the lack of expression of cancer/testis antigens (CTA) in normal tissues, these antigens are partially able to induce immune responses in cancer patients. Therefore, they are promising targets for immunotherapy. EFT are characterized by chromosomal rearrangements involving members of the TET (translocated in liposarcoma, Ewing sarcoma breakpoint region 1, TATA box binding protein-associated factor 15) family of RNA binding proteins and members of the E-26 (ETS) family of transcription factors. The resulting onco-fusion proteins are highly specific for EFT and downstream targets of TET-ETS represent candidate tumor specific antigens. In order to identify new EFT-associated CTA, we analyzed microarray-data sets from EFT and normal tissues from the Gene Expression Omnibus (GEO) database. The impact of TET-ETS on expression of CTA was analyzed using GEO data sets from transgenic mesenchymal stem cells. One CTA with high specificity for EFT is lipase I (LIPI, membrane-associated phospholipase A1-β). CTL specific for LIPI-derived peptides LDYTDAKFV and NLLKHGASL were able to lyse HLA-A2 positive EFT cells in vitro which confirms the possible role of LIPI and other CTA for EFT-immunotherapy.

Protein Expression of the Matrix Metalloproteinase (MMP-1, -2, -3, -9 and -14) in Ewing Family Tumors and Medulloblastoma of Pediatric Patients

The matrix metalloproteinases (MMP) are endopeptidases performing proteolytic functions in the extracellular matrix and their overexpression has been suggested to be a characteristic of malignant tumors. Molecular changes such as the presence of chimeric protein EWS-FLI1 in the Ewing family of tumors (EFT) and the oncogenes C-ERBB-2, N-MYC, C-MYC in medulloblastomas (MB) promote the overexpression of MMP. In the present study, protein expression of MMP -1, -2, -3, -9 and -14 was qualitatively evaluated in 17 EFT and MB samples of children and adolescent by Western Blotting and optical densitometry, and the level of gene expression of some MMPs was determined by RQ-PCR. Five MB samples (45.4%) presented expression of the 5 MMPs and 6 samples (54.6%) presented expression of at least one of them. Four EFT samples (66.6%) presented expression of MMP-2, -9 and -14, and two samples (33.4%) presented expression of at least one of these MMPs, whereas the presence of MMP-1 and -3 was not observed. Gene analysis showed that MMP-2 had a high expression in MB, while the expression of MMP-9 and MMP-14 was higher in EFT. It has been established that the expression of the MMPs might be related to a complex pathway of gene regulation.

Civil War Dynasty: The Ewing Family of Ohio

Civil War Dynasty: The Ewing Family of Ohio

A case of primary mediastinal Ewing′s sarcoma /primitive neuroectodermal tumor presenting with initial compression of superior vena cava

Ewing's sarcomas and peripheral primitive neuroectodermal tumors (ES/PNETs) are high grade malignant neoplasms. These malignancies are characterized by a chromosome 22 rearrangement, arise from bone or soft tissue, predominantly affect children and young adults, and are grouped in the Ewing family of tumors. Multimodality treatment programs are the treatment of choice. Primary localization of ES/PNET in the mediastinum is extremely rare. We describe a case of ES/PNET presenting as a mediastinal mass with tracheal compression and initial signs of superior vena cava in a 66-year-old woman.

Primary metastatic Ewing's family tumors: results of the Italian Sarcoma Group and Scandinavian Sarcoma Group ISG/SSG IV Study including myeloablative chemotherapy and total-lung irradiation

The Italian Sarcoma Group and the Scandinavian Sarcoma Group designed a joint study to improve the prognosis for patients with Ewing's family tumors and synchronous metastatic disease limited to the lungs, or the pleura, or a single bone. The study was opened in 1999 and closed to the enrollment in 2008. The program consisted of intensive five-drug combination chemotherapy, surgery and/or radiotherapy as local treatment, and consolidation treatment with high-dose busulfan/melphalan plus autologous stem cell rescue and total-lung irradiation. During the study period, 102 consecutive patients were enrolled. The median follow-up was 62 months (range 24-124). The 5-year event-free survival probability was 0.43 [standard deviation (SD) = 0.05] and the 5-year overall survival probability was 0.52 (SD = 0.052). Unfavorable prognostic factors emerging on multivariate analysis were a poor histological/radiological response at the site of the primary tumor [relative risk (RR) = 3.4], and incomplete radiological remission of lung metastases after primary chemotherapy (RR = 2.6). One toxic death and one secondary leukemia were recorded. This intensive approach is feasible and long-term survival is achievable in ∼50% of patients. New treatment approaches are warranted for patients responding poorly to primary chemotherapy.

Nuclear scintigraphy findings for Askin tumor with In111-pentetreotide, Tc99m-MIBI and F18-FDG.

Askin tumor is a rare disease which had previously been reported as being thallium-201 and gallium-67 avid. Varying data regarding 18F- fluorodeoxyglucose metabolism has been described with Ewing family of soft tissue tumors. In this case, we present a patient found to have an Askin tumor of the left chest wall which demonstrated indium-111 pentetreotide and technetium-99m MIBI avidity. The lesion did not show 18F- fluorodeoxyglucose hypermetabolism in this case despite the aggressiveness of the tumor. The patient was treated with surgical excision of the tumor and chemotherapy. Subsequently, contrast enhanced CT, indium-111 pentetreotide and technetium 99m-MIBI showed that the lesion had regressed. These findings suggest that Askin tumor can demonstrate Indium-111 pentetreotide and technetium 99m-MIBI uptake and need not be hypermetabolic on 18F-fluorodeoxyglucose exam.

EL23 - Sarcoma: Molecular-Targeted Therapies

ABSTRACT Sarcomas are rare heterogeneous malignant neoplasms that arise from mesenchymal tissues and are clinically divided into two main categories, that is, bone and soft tissue sarcomas. The overall frequency of sarcomas is ∼1% of all adult solid malignancies, and the incidence of bone sarcomas and soft-tissue sarcomas is estimated to be four patients per one million persons per year and two patients per 100 000 persons per year, respectively. Sarcomas are classified into various tumor types on the basis of histological characteristics, for example, osteosarcoma, Ewing family tumor, rhabdomyosarcoma, leiomyosarcoma, liposarcoma, and clear-cell sarcoma. In the last few decades, cytotoxic agents such as anthracycline agents and ifosfamide have been proven as key drugs for treating sarcomas. However, anthracycline based chemotherapy would not be optimal strategy for all histologic type of sarcomas. Recent advances in genomics, molecular biology, and molecular-targeted drug development have changed the treatment strategies for and prognosis of various cancers and hematological malignancies. Furthermore, the therapeutic developments for gastrointestinal stromal tumors constitute a successful paradigm that has affected the prognosis of such patients. However, dramatic changes in therapeutic strategy have not yet been achieved in other types of sarcomas, and many researchers continue to explore critical molecular targets for breakthroughs in treatment strategy. This educational session will introduce recent translational studies to investigate candidate molecular targets for sarcomas and promising molecular targeted drugs on the basis of the results of international phase III clinical trials on sarcomas. In the case of rare malignancies, the patient enrollment method in phase III clinical trials always has limitations with respect to achieving significant clinical benefits regarding aspects such as overall survival because each type of sarcoma is an essentially different neoplasm.

Utilisation of fluorescent multiplex PCR and laser-induced capillary electrophoresis for the diagnosis of Ewing family of tumours in formalin-fixed paraffin-embedded tissues

AimsThe localisation of the translocation breakpoint of the Ewing sarcoma family of tumours shows significant variability on relatively large regions of fusion partner genes. As a consequence, many alternative forms...

Tumeur neuroectodermique primitive des parties molles de l’index chez l’adulte. À propos d’un cas

The primitive neuroectodermal tumours (PNET) of soft tissues belong to the Ewing's tumors family and affects particularly the child. The localization of the disease at the extremities is very rare within the adult population and raises the problem of differential diagnosis with others tumors of the soft tissues. We report the case of a 48-year-old patient with a localized tumor, at the level of the second right finger, of six months evolution. The biopsy showed the infiltrating nature of the tumour; and the diagnosis of (PNET) was confirmed after the histological and immunohistochemical study. The extension assessment was negative and the patient had an amputation of the second and third rays of the right hand. Four years afterwards, the patient showed no recurrence or metastases.

Interval compressed vincristine, doxorubicin, cyclophosphamide alternating with ifosfamide, etoposide in patients with advanced Ewing’s and other Small Round Cell Sarcomas

BackgroundTo evaluate tolerability and maintenance of dose intensity of 2 weekly treatment with vincristine, doxorubicin, cyclophosphamide alternating with ifosfamide, etoposide (VDC/IE) in patients with advanced small round cell sarcomas including Ewing family tumours (EFT), desmoplastic small round cell tumours (DSRCT) and undifferentiated high grade round cell sarcomas (UHGRCS).MethodsRetrospective review of 16 patients treated at a single centre with VDC/IE. Dose received, treatment delay, toxicity and clinical outcome were recorded for each cycle up to a maximum of 14 cycles.ResultsA total 193 cycles of VDC/IE were administered to 10 patients with EFT, 4 with DSRCT and 2 with UHGRCS. Median age was 22 years with 75% over 18 years. Metastases were present in 14 patients. The mean duration of each cycle was 16.7 days. Febrile neutropenia occurred in 14 % of cycles, and grade 3/4 haematologic toxicity including anaemia and thrombocytopenia in 16 % and 11 % of cycles respectively. Seven patients had a dose reduction. Five patients discontinued VDC/IE early due to toxicity.ConclusionsThis schedule of VDC/IE is feasible in patients with EFT and DSRCT including adults and those with metastases. Its comparison with other standard regimens for these diseases is justified.

Playing Bad Cards Properly: Challenges to Improving Cure Rates in Rhabdomyosarcoma

“Success . . . comes not from having the right cards, but from playing bad ones properly.” —Joshua Dool. At least two thirds of children and adolescents with intermediateand higher-risk nonmetastatic rhabdomyosarcoma can be cured with multidisciplinary therapy. Although a reasonably good outcome, it clearly is not good enough. The total burden of therapy is high, with substantial acute and chronic toxicity. The best established therapy is a three-drug chemotherapy combination using vincristine, dactinomycin, and an alkylator (either cyclophosphamide or ifosfamide) and local control measures that cause substantial morbidity, particularly in our youngest patients. The therapy approach and anticipated outcome have not substantially changed in the last two decades. Oberlin et al report in Journal of Clinical Oncology the results of the MMT95 trial, a well-designed prospective, randomized study comparing intensified six-drug therapy versus standard three-drug chemotherapy in nonmetastatic rhabdomyosarcoma and other chemosensitive childhood soft tissue sarcomas. Intensification of chemotherapy provided no survival advantage, no reduction in the intensity of local therapy, and added toxicity—certainly not the answer for which these investigators had hoped. Why have we been unable to make any recent progress in treating rhabdomyosarcoma? Successful clinical trials must be well designed. Most advances in pediatric oncology have used prospective, randomized comparative study designs. However, good trial design certainly does not guarantee success. The two most recently completed intermediate-risk rhabdomyosarcoma studies conducted by the Intergroup Rhabdomyosarcoma Study (IRS) Group (IRS-IV comparing vincristine, dactinomycin, and cyclophosphamide [VAC]; vincristine, dactinomycin, and ifosfamide; and vincristine, ifosfamide, and etoposide) and the Children’s Oncology Group (COG; D9803 comparing VAC v VAC plus topotecan and cyclophosphamide) were well designed and appropriately powered and evaluated agents with substantial clinical activity, yet they failed to show any improvement in the experimental arms. The MMT95 (Malignant Mesenchymal Tumor 1995) study prospectively randomly assigned patients to receive threeor six-drug therapy, with a switch to the six-drug combination in patients who had disease progression, less than 50% imaging response, or poor histologic response. This design decreased the number of patients who received either only threeor only six-drug therapy. In addition, a relatively high number of eligible patients were not randomly assigned (149 of 606; 25%). However, these flaws, while decreasing the statistical power of this study, are relatively minor and do not seem to have affected the final negative results. Selection of the right patient population is a key component of sound clinical trial design. The MMT95 study enrolled higher-risk patients with rhabdomyosarcoma with both embryonal and alveolar histologies. These two histologies are biologically distinct, yet all cooperative group trials in higher-risk rhabdomyosarcoma have included both histologies, with few data to suggest substantial differences in treatment response for the different histologic entities. In addition, the MMT95 study enrolled 72 patients with chemotherapy-sensitive nonrhabdomyosarcoma soft tissue sarcomas. Soft tissue primitive neuroectodermal tumors (27 patients enrolled onto MMT95) share morphologic, immunohistochemical, and genetic features with Ewing tumors arising in bone, are classified by WHO inclusively as Ewing sarcoma/primitive neuroectodermal tumor, and are currently treated in studies of the Ewing family of tumors. COG trials previously enrolled patients with undifferentiated sarcomas together with rhabdomyosarcomas, but these patients were recently treated on a study for other nonrhabdomyosarcoma soft tissue sarcomas (COG ARST0332: Risk-based treatment for nonrhabdomyosarcoma soft tissue sarcomas in patients under30yearsofage).Ratesofmetastasis inMMT95werehigher inthese patient subsets (P .03); the number of patients enrolled with these histologies was insufficient to provide insights into the impact of more intensive therapy. Cure rates have improved in some childhood cancers with the optimization of chemotherapy schedules and doses. Decades of empiric adjustments using a modest number of active chemotherapy

Prognostic and diagnostic value of Ewing family of tumors (EFTs)-associated fusion transcripts detected in peripheral blood specimens.

10538 Background: EFTs are characterized by chromosomal translocations leading to formation of oncogenic EWSR1-FLI1 fusion gene in 85-90% of cases. The aim of the study was to detect circulating tumor cells (CTCs) carrying EWSR1-FLI1 fusion transcript in peripheral blood and assess their added value to standard diagnostic procedures and utility as a prognostic marker in EFTs. Methods: 10mL of whole blood was collected from 35 untreated adult EFTs patients at the diagnosis (period: 2008-2011, median age 27 years) and 13 healthy controls. 13 patients presented metastatic disease (M1) at the diagnosis. Nested RT-PCR was applied in triplicate for the detection of EWSR1-FLI1 transcript. Blood specimen was regarded CTC-positive when at least 2 out of 3 nested RT-PCR assays were positive and results were confirmed by sequencing. FISH assay for EWSR1 rearrangement was performed on FFPE tumor tissue in 28 available cases. Median follow-up was 16 months. Results: EWSR1-FLI1 transcript was detected in peripheral blood of 71.4% (n=25) of patients. FISH assay was positive for EWRS1 rearrangement in 58% of cases. In 10 patients, where FISH assay could not be performed due to insufficient quality or lack of material, nested RT-PCR provided confirmation of immunopathological diagnosis. Specificity of RT-PCR blood test in healthy control was 91.4% (12/13 negative; p=0.0001). Median overall survival (OS) was 18 months. CTC-positive patients showed the trend for longer OS than CTC-negative patients (1-year OS: 89% vs. 58%; p=0.07), but longer follow-up is needed. Conclusions: Our results show that the fusion transcript detection in peripheral blood specimens may be a useful additional test to the standard clinicopathological diagnosis of EFTs. High detection rate of EWSR1-FLI1 transcript in peripheral blood of EFTs patients at the diagnosis may imply EFTs as a systemic disease with clinically evident metastases or micrometastases at presentation. Prognostic significance of CTCs in EFTs warrants further studies.

Phase II Study of Ganitumab, a Fully Human Anti–Type-1 Insulin-Like Growth Factor Receptor Antibody, in Patients With Metastatic Ewing Family Tumors or Desmoplastic Small Round Cell Tumors

Ganitumab is a fully human monoclonal antibody against type-1 insulin-like growth factor receptor (IGF1R). An open-label phase II study was conducted to evaluate the efficacy and safety of ganitumab monotherapy in patients with metastatic Ewing family tumors (EFT) or desmoplastic small round cell tumors (DSRCT). Patients ≥16 years of age with relapsed or refractory EFT or DSRCT received 12 mg/kg of ganitumab every 2 weeks. Objective response rate (ORR) was the primary end point. Secondary end points included clinical benefit rate (CBR = complete + partial responses + stable disease [SD] ≥ 24 weeks) and safety and pharmacokinetic profiles of ganitumab. The relationship between tumor response and EWS gene translocation status and IGF-1 levels was evaluated. Thirty-eight patients (22 with EFT; 16 with DSRCT) received one or more doses of ganitumab. Twenty-four patients (63%) experienced ganitumab-related adverse events. Grade 3 related events included hyperglycemia (n = 2), thrombocytopenia (n = 5), neutropenia (n = 2), leukopenia (n = 1), and transient ischemic attack (n = 1). There were no grade 4 or 5 treatment-related events. Of 35 patients assessed for response, two had partial responses (ORR, 6%) and 17 (49%) had SD. Four patients had SD ≥ 24 weeks, contributing to a CBR of 17%. The pharmacokinetic profile of ganitumab was similar to that observed in the first-in-human trial. Elevation of IGF-1 levels was observed postdose. EWS-Fli1 translocations were analyzed by RNA sequencing and fluorescent in situ hybridization, and novel translocations were observed in EFT and DSCRT. No apparent relationship between tumor response and IGF-1 levels or EWS gene translocations was observed. Ganitumab was well tolerated and demonstrated antitumor activity in patients with advanced recurrent EFT or DSRCT.

Abstract 431: ErbB4 is a novel driver of metastasis and anoikis resistance in Ewing's sarcoma

Abstract Most Ewing family tumor (EFT) related deaths occur as a consequence of metastatic disease. Using high-throughput Affymetrix arrays, and matched primary and metastatic tumor-derived cell line pairs, we have identified ERBB4, a member of the epidermal growth factor receptor (EGFR) family, as a novel driver of metastasis and anoikis resistance in EFTs. Gene expression profiling, mRNA analysis, and immunoblotting revealed a 2 to 4-fold increase in ERBB4 expression in metastatic compared to primary EFT cell lines. SNP profiling failed to show copy number aberrations to explain the increased ErbB4 expression in metastatic cell lines. However, epigenetic mechanisms were found to potentially regulate ERBB4 expression in the paired CHLA-9 primary and in the metastatic/chemoresistant CHLA-10 cell line derived from the same patient. Treatment with 5-aza-2α-deoxycytidine enhanced ErbB4 in CHLA-9 cells, but reduced its expression in CHLA-10, suggesting a potential role for DNA methylation in controlling ERBB4 expression in EFTs. Enhanced protein expression and ErbB4 tyrosine kinase activation were clearly identified in metastatic versus primary cells grown under anchorage independent conditions (as multicellular spheroids), which mimic micrometastases. We next evaluated the clinical relevance of these data using biopsies from EFT patients. We found a direct correlation between ErbB4 expression and reduced disease-free survival (p&amp;lt;0.05), and identified statistically higher ErbB4 expression (p&amp;lt;0.05) in metastatic vs. primary biopsies (80% vs. 56%, respectively). ErbB4 gene knockdown or treatment with the FDA-approved pan-ErbB inhibitor Lapatinib reduced proliferation, blocked cell migration and tumor invasion, and sensitized metastatic/chemoresistant cell lines to EFT standard of care chemotherapeutic drugs. Taken together, our findings identify ErbB4 as a novel driver of metastasis in EFTs. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 431. doi:1538-7445.AM2012-431