Anti-angiogenic anticancer therapies possess immune-stimulatory properties by counteracting pro-angiogenic molecular mechanisms. We report that tumor endothelial cells ubiquitously overexpress and secrete the intermediate filament protein vimentin through type III unconventional mechanisms. Extracellular vimentin is pro-angiogenic and functionally mimics VEGF action, while concomitantly acting as inhibitor of leukocyte-endothelial interactions. Targeting of extracellular vimentin presents a promising anti-angiogenic immunotherapy strategy against cancer. Here we describe profiling of the HUVEC (Human Umbilical Vein Endothelial Cell) proteome, with special emphasis on vimentin (variants) in the different fractions. We have evidence that vimentin is externalized and deposited in the matrix of cultured cells and is as such available for targeted antiangiogenic therapeutics. The aim of the experiment is to determine the protein variants of vimentin in the cell, the secretome, and in the matrix deposited by the cells.