ABSTRACT
The tumor vasculature is an important target for both cancer therapy and imaging. Angiogenesis, the growth of new capillary blood vessels, is the process by which cancer cells recruit their vasculature. Tumor growth is dependent upon angiogenesis, because new vessels provide circulatory perfusion and deliver a host of survival factors to proliferating cancer cells. The angiogenic process in cancer shares similarities with neovascularization occurring under physiological situations, e.g. wound healing (granulation), or female reproductive function (endometrial regeneration, corpus luteum formation, placentation), but possesses unique features that distinguish the tumor vasculature from normal blood vessels. The tumor vasculature is characterized by aberrant vascular architecture, hyperpermeability, disruptions in arterial-venous hierarchy, and regional areas of stasis. Excessive vascular permeability leads to intratumoral edema and increased intratumor interstitial pressure, resulting in forces that compress the tumor vasculature and limit perfusion, as well as the intravascular delivery of cancer drugs.
