Aberrant chromosomal fusion of the Ewing's sarcoma oncogene (EWS) to several different cellular partners produces the Ewing's family of oncoproteins (EWS-fusion-proteins, EFPs) and associated tumors (EFTs). EFPs are potent transcriptional activators, dependent on the N-terminal region of EWS (the EWS-activation-domain, EAD) and this function is thought to be central to EFT oncogenesis and maintenance. Thus EFPs are promising therapeutic targets, but detailed molecular studies will be pivotal for exploring this potential. Such studies have so far largely been restricted to intact mammalian cells while recent evidence has indicated that a mammalian cell-free transcription system may not support bona fide EAD function. Therefore, the lack of manipulatable assays for the EAD presents a significant barrier to progress. Using Xenopus laevis oocytes we describe a plasmid-based micro-injection assay that supports efficient, bona fide EAD transcriptional activity and hence provides a new vehicle for molecular dissection of the EAD.
Animals ; Biological Assay ; Female ; Oncogene Proteins ; genetics ; Oncogenes ; genetics ; Oocytes ; metabolism ; pathology ; RNA-Binding Protein EWS ; genetics ; metabolism ; Sarcoma, Ewing ; genetics ; pathology ; Xenopus

Extraskeletal Ewing's sarcoma (EES) is a branch of neuroectodermal tumor (PNET), which is very rare soft tissue sarcoma. We report a case of EES/PNET arising is the lung of a 67-yr-old man. Computed tomography, bone scintigraphy, and positron emission tomography confirmed the mass to have a primary pulmonary origin. The mass showed positive reactivity in the Periodic Acid Schiff (PAS) stain and MIC-2 immunoreactivity in immunohistochemical stain. Fluorescence in situ hybridization (FISH) was performed, which revealed an EWSR1 (Ewing sarcoma breakpoint region 1) 22q12 rearrangement. The diagnosis was confirmed both pathologically and genetically. The mass lesion was resected, and the patient is currently undergoing chemotherapy.
Aged ; Calmodulin-Binding Proteins/genetics ; Chromosome Breakage ; Chromosomes, Human, Pair 22/genetics ; Diagnosis, Differential ; Humans ; Immunohistochemistry ; In Situ Hybridization, Fluorescence ; Lung Neoplasms/*diagnosis/genetics/metabolism/pathology ; Male ; Neuroectodermal Tumors, Primitive, ; RNA-Binding Proteins/genetics ; Sarcoma, Ewing's/*diagnosis/genetics/metabolism/pathology

Extraskeletal Ewing's sarcoma (EES) is a rare soft tissue tumor morphologically indistinguishable from the more common Ewing's sarcoma of bone. We report a case of EES arising in the hard palate of 34-yr-old male patient. Microscopically, the monotonous small round cells without neuronal differentiation showed membranous positive immunoreactivity for MIC2/CD99 and vimentin. Ultrastructurally, the tumor cells showed a few intracytoplasmic organelles without evidence of neurosecretory granules or neurofilaments. The EWS-FLI1 chimeric gene was identified using the nested reverse transcriptase-polymerase chain reaction.
Adult ; Antigens, CD/analysis ; Cell Adhesion Molecules/analysis ; Humans ; Immunohistochemistry ; Male ; Oncogene Proteins, Fusion/genetics ; Palatal Neoplasms/genetics/metabolism/*pathology ; Palate, Hard/metabolism/*pathology ; Proto-Oncogene Protein c-fli-1/genetics ; Reverse Transcriptase Polymerase Chain Reaction ; Sarcoma, Ewing's/genetics/metabolism/*pathology ; Transcription, Genetic ; Vimentin/analysis