Use

FLI‑1 (Friend leukemia integration 1) is a nuclear transcription factor and has been reported as the first nuclear marker of endothelial differentiation. It labels hemangiomas, angiosarcomas, Kaposi’s sarcoma, Ewing’s sarcoma, and Merkel cell carcinoma, and is also expressed in normal endothelial cells, megakaryocytes, and normal breast epithelium. This immunohistochemical marker assists in the identification and differential diagnosis of vascular and round cell neoplasms in a technical immunostaining context.