title: Immunoreactivity using anti-ERG monoclonal antibodies in sarcomas is influenced by clone selection.
abstract: The aim of the present study was to explore ERG immunoreactivity in a series of sarcomas, GIST and malignant rhabdoid tumor (MRT), considering the not fully elucidated specificity and sensitivity of this antibody. Paraffin-embedded tissue microarrays from those tumors were stained with anti-ERG against the C-terminus [(EPR3864(2)] and N-terminus (Clone 9FY). EPR3864(2) was positive in almost all angiosarcomas, and MRT.GIST were positive in a large proportion of cases (38.4%), and more than half the synovial sarcomas (52.7%) revealed EPR3864(2) staining. Several chondrosarcomas, osteosarcomas, rhabdomyosarcoma and Ewing's sarcoma family of tumors (ESFT) presented EPR3864(2) expression in a lower number of cases. 9FY was positive in most of the angiosarcomas; however, only sporadic ESFT and synovial sarcoma were positive and the other tumors tested were negative. Fourteen ESFT with EWSR1/Fli-1 gene fusion presented positive nuclear staining for EPR3864(2). Similarly, 5 ESFT with EWSR1/Fli-1 gene fusion presented positive staining for 9FY. We must stress that the difference between the present and previous studies may be due to the source of the anti-ERG employed, anti-ERG against C or N-terminus, protein cross-reactivity and dilution. In conclusion, specificity for ERG staining in sarcomas should be considered with caution and the immunoexpression is undoubtedly influenced by clone and antibody selection.
authors.affiliation: Department of Pathology, Instituto Valenciano de Oncología, Valencia, Spain; Department of Pathology, University of Valencia, Valencia, Spain.
authors.forename: Isidro
authors.initials: I
authors.lastname: Machado
authors.affiliation: Department of Pathology, University Hospital "La Fe", Valencia, Spain; Department of Pathology, University of Valencia, Valencia, Spain.
authors.forename: Empar
authors.initials: E
authors.lastname: Mayordomo-Aranda
authors.affiliation: Department of Pathology and Research, Rizzoli Orthopedic Institute, Bologna, Italy; Department of Pathology, University of Valencia, Valencia, Spain.
authors.forename: Katia
authors.initials: K
authors.lastname: Scotlandi
authors.affiliation: Department of Pathology and Research, Rizzoli Orthopedic Institute, Bologna, Italy; Department of Pathology, University of Valencia, Valencia, Spain.
authors.forename: Piero
authors.initials: P
authors.lastname: Picci
authors.affiliation: Department of Pathology and Research, Rizzoli Orthopedic Institute, Bologna, Italy; Department of Pathology, University of Valencia, Valencia, Spain. Electronic address: Antonio.llombart@uv.es.
authors.forename: Antonio
authors.initials: A
authors.lastname: Llombart-Bosch
mesh_terms: D000911:Antibodies, Monoclonal; D001932:Brain Neoplasms / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D046152:Gastrointestinal Stromal Tumors / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods*; D007680:Kidney Neoplasms / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D012189:Retrospective Studies; D018335:Rhabdoid Tumor / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D012509:Sarcoma / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D012680:Sensitivity and Specificity; D015534:Trans-Activators / Q000378:metabolism*; D000071230:Transcriptional Regulator ERG
chemical_list: D000911:Antibodies, Monoclonal; C072312:ERG protein, human; D015534:Trans-Activators; D000071230:Transcriptional Regulator ERG
keywords: ERG; Ewing's sarcoma; Immunohistochemistry; Sarcomas