{"type":"root","children":[{"type":"paragraph","children":[{"type":"text","value":"Fli-1 protein, a member of the ETS family of DNA binding transcription factors, is involved in cellular proliferation and tumorigenesis. Approximately 90% of Ewing’s Sarcoma/Primitive Neuroectodermal Tumors (ES/PNET) have a specific translocation, t(11;22)(q24;q12), which results in fusion of EWS to Fli-1, and production of an EWS-Fli-1 fusion protein, which can be detected by this antibody. Among normal tissues only endothelial cells and small lymphocytes express Fli-1. Fli-1 has been found to be expressed in the great majority of vascular tumors including Angiosarcomas, Hemangioendotheliomas, Hemangiomas, and Kaposi’s Sarcomas.\n It has been reported that the high sensitivity and specificity of Fli-1 is equal to or exceeds that of the established vascular markers, CD31, CD34, and Factor VIII. As the first nuclear marker of endothelium (rather than cytoplasmic or membranous), Fli-1 immunostaining also generally lacks cytoplasmic staining artifacts that are the result of endogenous peroxidases or biotin."}]}]}