Figure 4. Targeting the Angiopoietins in Cancer Therapy.

(A) Ang1 is constitutively expressed in low levels in healthy adults and maintains endothelial quiescence (Pfaff et al, 2006). (B) In many cancer types, overexpression of Ang2 and increased Ang2/Ang1 ratios correlate with more advanced disease stages and worse prognosis (Huang et al, 2010). (C) There are Ang2‐neutralizing agents already in clinical development as oncologic drugs, as well as preclinical investigatory agents activating Tie2.