Mast cells and macrophages exert beneficial and detrimental effects on tumor progression and angiogenesis

• Mast cells and macrophages are critical regulators of inflammation and immunological response in the tumor microenvironment..
• Mast cell- and macrophages-derived growth factors are able to promote tumor development and angiogenesis.
• Therapeutic strategies include inhibition of recruitment of mast cells and macrophages to the tumor microenvironment and blockade of pro-tumoral effects and pro-angiogenic functions.

Mast cells and macrophages are critical regulators of inflammation and immunological response in the tumor microenvironment. Increased number of mast cells and macrophages have been reported to correlate with poor prognosis in numerous solid and hematological tumors. In contrast to their pro-tumorigenic role, mast cells and macrophages have shown also anti-tumorigenic effect in certain malignancies, for example by supporting cancer rejection. Thus, mast cells and macrophages can exert both detrimental and beneficial effects on tumor progression. Mast cell- and macrophages-derived growth factors able to promote tumor development and angiogenesis include TNF-α, TGF-β1, FGF-2, VEGF, PDGF, IL-8, osteopontin, and NGF. On the contrary, mast cell- and macrophages-produced cytokines that may participate in anti-tumor response include IL-1, IL-2, IL-4, IL-10, and IFN-γ. It is to note that mast cells and macrophages may also show beneficial and detrimental effects in the same cancer depending on the tumor stage.