 I. To evaluate tumor tissue expression of endoglin CD105, transforming growth factor, beta receptor II TGFBR2, activin A receptor type II-like 1 ACVRL1 and transforming growth factor, beta receptor 1 TGFBR1 kinase from pre- and post-treatment tissue samples in order to determine whether CD105 and stem cell activation occurs after exposure to anti-vascular endothelial growth factor VEGF therapy as predicted by laboratory models, and whether exposure to anti-endoglin monoclonal antibody TRC105 affects these changes. 