Taken together we identify for the first time a vascular endothelial phenotype in BAMBI−/− mice, and provide evidence for a physiological role for BAMBI in endothelial biology and vascular homeostasis, observations that may be of considerable interest for the modification of the vascular actions of TGFβ by BAMBI, including neo-angiogenesis during tissue injury and during tumor growth. This evidence concerns the gene BAMBI and neoplasm.