A double-edged sword in tumor angiogenesis and progression. Dual roles of mast cells, macrophages, and neutrophils

Inflammatory cells act in concert with tumor cells, stromal cells, and endothelial cells to create an environment that is critical for the survival, development, and diffusion of the tumor. Under a variety of conditions, inflammatory cells are capable of polarization under their tumoricidal (growth arresting) or tumorigenic (growth promoting) forms. In this context, two major subsets of mast cells, macrophages, and neutrophils, have been described. This article is focused on the description of these different sub-populations and to the analysis of arrays of common and specific mediators involved in their action in the context of tumor growth. Different databases, including PubMed/MEDLINE, Scopus, and Google Scholar, were searched to review and analyze relevant literature concerning the different sub-populations of mast cells, macrophages, and neutrophils, and arrays of common and specific mediators involved in their action in the context of tumor growth.The analysis of the literature data confirm that the microenvironment can inhibit tumor growth and suppress or revert the malignant phenotype. Incorrect signals from the microenvironment can lead to initiation and promotion of neoplastic transformation of normal cells, and once tumor is formed, it modifies the stroma and initiates an inflammatory reaction and an immune response.