VEGFA and neoplasm: The following mechanisms are potential ways in which Ang-2 promotes angiogenesis (27–29): (1) Ang-2 antagonizes the effect of Ang-1 on Tie-2, which inhibits Tie-2 signaling and disrupts signals mediating stable endothelial cell interaction in the Tie-2 signaling pathway, leading to the instability for existing blood vessels; and (2) Ang-2 and VEGF synergistically promote the formation of tumor blood vessels.