Fig. 2
From: Angiogenic signaling pathways and anti-angiogenic therapy for cancer
Most common modes in tumor angiogenesis. a Sprouting angiogenesis: main way in both physiological and pathological angiogenesis, which is induce by proliferation and migration of endothelial tip cells. b Intussusception: the existing blood vessel is divided into two vessels under mediation of cell reorganization. c Vasculogenesis: bone-marrow-derived endothelial progenitor cells differentiate into endothelial cells, participating in the formation of new vascular lumen. d Vessel co-option: tumor cells approach and hijack the existing blood vessels. e Vessel mimicry: tumor cells form a vessel-like channel around normal blood vessels to direct the transport of oxygen and nutrients into tumor tissue. f Trans-differentiation of cancer cells: cancer stem-like cells differentiate into endothelial cells, which participate in the formation of new blood vessels. (Modified from Carmeliet, P. & Jain, R. K. Molecular mechanisms and clinical applications of angiogenesis. Nature 473, 298–307 (2011).)
