Tumor associated macrophage: a review on the phenotypes, traits and functions

The macrophages role within the tumor microenvironment has amended by a variety of factors, thus serves a vital role in tissue morphogenesis. The role of macrophages in health and disease differs enormously as the macrophage has shown dual functions. Macrophage has a basic role in antigen presentation serving as the first line of defense in diseases. However the presence of cytokines and growth factors, both together have regulated the macrophage to become negative effectors promoting tumor activity. Hence macrophages are a double edged weapon, and any imbalance in the regulatory mechanisms caused a shift from tumoricidal to tumorigenic activities. TAMs would be the main reason of the invasion in tumor microenvironment enhancing as well as tumor invasion, angiogenesis and metastasis promoting tumor genesis. Macrophages are the multifunctional cells which have conducted by the tumor cells to produce tumor promoting factors that enable the stimulation of angiogenesis, and tumor cell invasion. This fact has resulted initiation or promotion of tumor genesis, where the tumor has progressed to an upper malignant stage. The present review has focused on the tumor associated macrophages and their roles in tumor genesis.