TIE1 and neoplasm: However our data demonstrating that tumor angiogenesis and VEGF-induced angiogenesis in vivo were not affected in either pSico-Rac1-infected wild-type/Tie1-Cre+ mice or tamoxifen-treated Rac1 flox/flox PDGFB-iCreER mice, imply that angiogenic processes such as proliferation, migration and tube formation in vivo are not affected by the induced-loss of Rac1 in adult endothelial cells.