Research advances in role of tumor-associated macrophages

Macrophage is a diverse phenotype that has important functions in inherent and adaptive immunity. The macrophages can be induced into classical activation type (M1 phenotype) and alternative activation type (M2 phenotype) under different tumor microenvironment. This large number of activated macrophages infiltrate the tumor stroma and are referred to as tumor-associated macrophages. TAMs present M2 phenotype mostly and can secrete active substance to promote tumor growth, invasion and metastasis. The clarification of the role of macrophage phenotypes in tumor tissues and their developmental processes make it possible to target cancer treatment centered on macrophages.