Zeta FLI-1 Antibody. Zeta’s rabbit recombinant antibody recognizes FLI-1 (Friend Leukemia Integration 1), a DNA binding transcription factor involved in cellular proliferation and tumorigenesis. Zeta’s FLI-1 antibody recognizes a protein of 51kDa. FLI-1 is a member of the ETS family of DNA binding transcription factors which share a highly conserved carboxy-terminal domain containing a sequence related to the SV40 large T antigen nuclear localization signal sequence.
Pathologists use FLI-1 to differentiate Ewing Sarcoma (EWS) from other round blue cell tumors, to distinguish EWS of kidney (positive) from blastema predominant Wilms tumor (negative), to distinguish EWS (positive) from small cell osteosarcoma or mesenchymal chondrosarcoma (negative), and to diagnose benign and malignant vascular tumors.
FLI-1 is involved 90% of Ewing’s Sarcoma and Primitive Neuroectodermal Tumors (PNET) which have a specific translocation resulting in the fusion of EWS to FLI-1 and production of an EWS-FLI-1 fusion protein. Among normal tissues, only endothelial cells and small lymphocytes express FLI-1. The FLI-1 protein is expressed in most vascular tumors, including angiosarcomas, hemangioendotheliomas, hemangiomas, and Kaposi’s Sarcomas. The high sensitivity and specificity of FLI-1 equal or exceed that of the established vascular markers like CD31, CD34, and Factor VIII.