The roles of CSFs on the functional polarization of tumor-associated macrophages

International audienceMacrophages have a central role in numerous physiological processes, such asimmune defense, maintenance of tissue homeostasis, wound healing, andinflammation. Moreover, in numerous severe disorders, such as cancer orchronic inflammation, their functions can be profoundly affected. Macrophagescontinuously sense their environment and adapt their phenotypes andfunctions to the local requirements; this process is called plasticity. In additionto stress signals, metabolites, and direct cell-contact interactions with surroundingcells, numerous cytokines play a central role in controlling macrophagepolarization. In this review, we will focus on three human macrophagedifferentiation factors: macrophage colony-stimulating factor (M-CSF), IL-34,and granulocyte M-CSF. These CSFs allow human monocyte survival, promotetheir differentiation into macrophages, and control macrophage polarizationas they give rise to cells with different phenotype and functions. Basedon recent observations, the role of granulocyte CSF on macrophage polarizationis also addressed. Finally, our current knowledge on the expression ofthese growth factors in tumor microenvironment and their impact on the generationand polarization of tumor-associated macrophages are summarized