Figure 1.

Tumor angiogenic cascade.

Notes: Quiescent endothelial cells become activated when stromal, tumor, and immune cell-derived pro-angiogenic factors are secreted into the tumor site leading to proliferation migration, ECM degradation, and tube formation from existing capillaries. BMD EPCs are recruited to the tumor site and differentiate into endothelial cells, forming de novo capillaries (vasculogenesis). The resulting tumor blood vessels are morphologically and functionally distinct from normal vasculature.

Abbreviations: bFGF, basic fibroblast growth factor; BMD, bone marrow-derived; CAF, cancer associated fibroblasts; EC, endothelial cell; ECM, extracellular matrix; EGF, epidermal growth factor; EPC, endothelial progenitor cell; IL-8, interleukin 8; IL-17, interleukin 17; MMP, matrix metallopeptidase; PDGF, platelet-derived growth factor; SDF-1, stromal cell-derived factor 1; TAM, tumor-associated macrophages; TNF-α, tumor necrosis factor alpha; uPA, urokinase plasminogen activator; uPAR, urokinase plasminogen activator receptor; VEGF, vascular endothelial growth factor.