Figure 3

Eosinophils in tumor promotion. A microenvironment involving rapidly dividing cells induces tumor necrosis and the production of damage associated molecular patterns (DAMPs) which include the RAGE ligands (e.g.: HMGB1 and S100 proteins). Eosinophils and additional innate immune cells (microglia, mast cells, neutrophils) are activated by GBM mediators (GM-CSF, PDGF, CXCL12, CXCL8) and DAMPs which may in turn induce the production of growth factors (amphiregullin, TGF-α, VEGF) and matrix metalloproteinases in promoting tumorigenesis. Alternatively, in certain cases, eosinophil release of cytotoxic granules (EDN, ECP, calprotectin) may function to prevent tumor promotion.