Undifferentiated Small Round Cell Sarcomas with Rare EWS Gene Fusions

Department of Pathology, Memorial Sloan-Kettering Cancer Center, 1275 York Ave., New York, NY 10021, USA.
Journal of Molecular Diagnostics (Impact Factor: 4.85). 10/2007; 9(4):498-509. DOI: 10.2353/jmoldx.2007.070053
Source: PubMed


Ewing family tumors (EFTs) are prototypical primitive small round blue cell sarcomas arising in bone or extraskeletal soft tissues in children or adolescents. EFTs show fusions of EWS with a gene of the ETS family of transcription factors, either EWS-FLI1 (90 to 95%) or EWS-ERG (5 to 10%). Rare cases with fusions of EWS to other ETS family genes, such as ETV1, E1AF, and FEV, have been identified, but their clinicopathological similarity to classic EFTs remains unclear. We report four new cases of EFT-like tumors with rare EWS fusions, including two with EWS-ETV1, one with EWS-FEV, and a fourth case in which we cloned a novel EWS-SP3 fusion, the first known cancer gene fusion involving a gene of the Sp zinc finger family. Analysis of these three new cases along with data on nine previously reported cases with fusions of EWS to ETV1, E1AF, or FEV suggest a strong predilection for extraskeletal primary sites. EFT-like cases with fusions of EWS to non-ETS translocation partners are also uncommon but involve the same amino-terminal portion of EWS, which in our novel EWS-SP3 fusion is joined to the SP3 zinc-finger DNA-binding domain. As these data further support, these types of EWS fusions are associated with primitive extraskeletal small round cell sarcomas of uncertain lineage arising mainly in the pediatric population.

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Available from: Leonard H Wexler, Aug 21, 2014
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    • "More cases need to be studied to determine the significance and incidence of this abnormality in ES. It is also important to determine whether additional structural chromosomal aberrations are present in ES tumors because it appears that a more complex karyotype with multiple chromosomal aberrations is associated with a poor outcome in ES.[1617] "
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    ABSTRACT: Cytogenetic or immunohistochemical studies are often required to differentiate Ewing's sarcoma (ES) from other small round cell tumors. Herein we report a case of 13-year-old boy who presented with a large presacral lesion. Hemogram and biochemical parameters were normal except lactate dehydrogenase showing value of 96.40/IU/L, magnetic resonance imaging of the spine showed a large mass in presacral lesion (8 cm × 7 cm × 9 cm), with destruction of the sacrum (S2 S3 and S4) with interspinal extension. Bone scan showed multiple pelvic bone lesions, radiograph of chest, ultrasound of abdomen, pelvis and electrocardiogram were within normal limits. Bone marrow was not involved. Cells from the fine needle aspirate were cultured for short term using RPMI medium and karyotype obtained showed a t(12;22)(p12;q12) instead of the classic t(11;22). Diagnosis of ES was also confirmed by studies using immunohistochemistry for MIC2 which was positive, synaptophysin was inconclusive and leukocyte common antigen, desmin negative. This case provides evidence of the importance of chromosome 22, in the etiology of the disease.
    Full-text · Article · Apr 2014 · Indian journal of medical and paediatric oncology
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    • "The chimeric EWS-FLI1 oncoprotein alters the regulation of wild type FLI1 transcriptional targets [4], [5]. In a minority of cases, the EWS gene is fused to other ETS-family transcriptional factors such as ERG and ETV1 [6], [7]. Previous studies have shown that depletion of EWS-FLI1 results in cell cycle arrest and apoptosis in Ewing sarcoma cells [8], [9], [10], indicating that EWS-FLI1 may be an attractive therapeutic target [11], [12]. "
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    ABSTRACT: Fusion of the EWS gene to FLI1 produces a fusion oncoprotein that drives an aberrant gene expression program responsible for the development of Ewing sarcoma. We used a homogenous proximity assay to screen for compounds that disrupt the binding of EWS-FLI1 to its cognate DNA targets. A number of DNA-binding chemotherapeutic agents were found to non-specifically disrupt protein binding to DNA. In contrast, actinomycin D was found to preferentially disrupt EWS-FLI1 binding by comparison to p53 binding to their respective cognate DNA targets in vitro. In cell-based assays, low concentrations of actinomycin D preferentially blocked EWS-FLI1 binding to chromatin, and disrupted EWS-FLI1-mediated gene expression. Higher concentrations of actinomycin D globally repressed transcription. These results demonstrate that actinomycin D preferentially disrupts EWS-FLI1 binding to DNA at selected concentrations. Although the window between this preferential effect and global suppression is too narrow to exploit in a therapeutic manner, these results suggest that base-preferences may be exploited to find DNA-binding compounds that preferentially disrupt subclasses of transcription factors.
    Full-text · Article · Jul 2013 · PLoS ONE
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    • "Two different breakpoints have been identified for production of EWSR1/SP3 transcripts, involving EWS exon 7 with SP3 exon 6 and EWS exon 8 with SP3 exon 6. The fusion transcripts have been detected in undifferentiated small round cell sarcomas [78]. "
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    ABSTRACT: Soft tissue tumors are a heterogeneous group of tumors, traditionally classified according to morphology and histogenesis. Molecular classification divides sarcomas into two main categories: (a) sarcomas with specific genetic alterations and (b) sarcomas showing multiple complex karyotypic abnormalities without any specific pattern. Most chromosomal alterations are represented by translocations which are increasingly detected. The identification of fusion transcripts, in fact, not only support the diagnosis but also provides the basis for the development of new therapeutic strategies aimed at blocking aberrant activity of the chimeric proteins. One of the genes most susceptible to breakage/translocation in soft tissue tumors is represented by Ewing sarcoma breakpoint region 1 (EWSR1). This gene has a large number of fusion partners, mainly associated with the pathogenesis of Ewing's sarcoma but with other soft tissue tumors too. In this review, we illustrate the characteristics of this gene/protein, both in normal cellular physiology and in carcinogenesis. We describe the different fusion partners of EWSR1, the molecular pathways in which is involved and the main molecular biology techniques for the identification of fusion transcripts and for their inhibition.
    Full-text · Article · Mar 2013 · Medical Oncology
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