The Impact of M1/M2 Tumor Associated Macrophage (TAM) Polarization on Cancer Progression and Prognosis Prediction

Inflammatory response in the tumor micro-environment may facilitate the metastatic process (1). Macrophages are pivotal members of the inflammatory cells and the innate immune system within the tumor stroma. Tumor-associated macrophages can release growth factors, cytokines and inflammatory mediators that may facilitate cancer cell invasion, migration, angiogenesis, tumor progression or metastasis (1-5). A lot of studies showed TAM encounter factors that most frequently polarize them toward M2 type macrophage (1,4-5). It is interesting that in vitro studies macrophages have the potential to kill tumor by appropriate stimulation but these macrophage belonged to M1 and were not present in most tumor tissue (6). Some drugs target to suppress TAM have the promising results in animal models (7-9). Switching the TAM phenotype from M2 to M1 may promote anti-tumor activity (10). In this study we will correlate TAM M1/M2 ratio and patients' prognosis, the gene expression pattern of TAM.

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