Research Article

Low Concentration of S100A8/9 Promotes Angiogenesis-Related Activity of Vascular Endothelial Cells: Bridges among Inflammation, Angiogenesis, and Tumorigenesis?

Figure 5

Roles of S100A8/A9 in tumorigenesis. In this hypothesis, S100A8/A9 are produced by newly formed tumor cells or infiltrating leukocytes. When they reach adequately low concentrations, they can stimulate (1) tumor cells proliferation, (2) vascular endothelial cell proliferation, migration, and formation of vascular structures, and (3) neutrophils to migrate into tumor mass or adhere to endothelium. By producing S100A8/A9, the newly entering neutrophils enhance local inflammation and neovascularization in turn. Other S100A family members like S100A4, S100A7, and S100A13 may join S100A8 and/or S100A9 in this episode as well.
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