title: A novel EWSR1-CREB3L1 fusion transcript in a case of small cell osteosarcoma.
abstract: Cellular morphology of small cell osteosarcoma, an aggressive variant of osteosarcoma, is similar to Ewing sarcoma, but its molecular pathogenesis is largely unknown. We report the case of a 12-year-old girl with multifocal small cell osteosarcoma positive for the Ewing sarcoma breakpoint region 1 (EWSR1) gene rearrangement by interphase fluorescent in situ hybridization and negative for EWSR1-FLI1, EWSR1-ERG, and EWSR1-WT1 fusion transcripts by reverse transcriptase PCR. Rapid amplification of cDNA ends revealed exon 6 of the cAMP-responsive element binding protein 3-like 1 gene (CREB3L1, also known as "OASIS," NM_52854.2) fused in-frame to the EWSR1 exon 11, consistent with the EWSR1-CREB3L1 fusion transcript expressed in tumor tissue. The corresponding chimeric gene was confirmed by amplification and subsequent sequencing of the genomic breakpoint between introns 11 and 5 of EWSR1 and CREB3L1, respectively. An ∼70 kDa product in the tumor tissue lysate reacted with the CREB3L1 carboxyterminal antibody, consistent with a 656-amino acid predicted chimeric protein. Immunohistochemistry with the same antibody showed signal translocation from the physiologic perinuclear compartment observed in glia and unrelated osteoblasts to nuclei of tumor cells, consistent with the likely function of EWSR1-CREB3L1 as a transcriptional regulator predicted by its structure. This is the first report of a fusion transcript in osteogenic sarcoma; it demonstrates a relation between molecular mechanisms of small cell osteogenic and Ewing sarcomas. The 3'-end partner and the inferred structure of EWSR1-CREB3L1, however, are different from those of Ewing sarcoma, suggesting different targets of the new oncogene.
authors: Department of Pathology, Wayne State University, Detroit, MI, USA. ldebelen@med.wayne.edu.
authors: Larisa V
authors: LV
authors: Debelenko
authors: Lisa M
authors: LM
authors: McGregor
authors: Bangalore R
authors: BR
authors: Shivakumar
authors: Howard D
authors: HD
authors: Dorfman
authors: Susana C
authors: SC
authors: Raimondi
mesh_terms: D001483:Base Sequence; D002148:Calmodulin-Binding Proteins / Q000235:genetics*; D002467:Cell Nucleus / Q000235:genetics; D002648:Child; D017362:Cyclic AMP Response Element-Binding Protein / Q000235:genetics*; D005091:Exons; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence / Q000379:methods; D007438:Introns; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000235:genetics*; D009457:Neuroglia / Q000378:metabolism; D015514:Oncogene Proteins, Fusion / Q000235:genetics*; D012516:Osteosarcoma / Q000235:genetics*; D034802:RNA-Binding Protein EWS; D016601:RNA-Binding Proteins / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D018228:Sarcoma, Small Cell / Q000235:genetics*; D014178:Translocation, Genetic
chemical_list: C485618:CREB3L1 protein, human; D002148:Calmodulin-Binding Proteins; D017362:Cyclic AMP Response Element-Binding Protein; C500986:EWSR1 protein, human; D009419:Nerve Tissue Proteins; D015514:Oncogene Proteins, Fusion; D034802:RNA-Binding Protein EWS; D016601:RNA-Binding Proteins