To evaluate angiogenesis and neovascularization of Zfp36fl/fl and Zfp36ΔEP papillomas, we performed immunofluorescent staining for VE-Cadherin (an endothelial marker) and endoglin, a transmembrane glycoprotein expressed on activated vascular endothelial cells (20). This evidence concerns the gene CDH5 and papilloma.