MMP9 and neoplasm: CCL2–CCR2 immunosuppressive sequelae include the transition of tumor-associated macrophages (TAMs) to M2-type macrophages, recruitment of regulatory T-cells with enhanced production of suppressive cytokines such as IL-10, inhibition of apoptosis and autophagy in the setting of nutrient deprivation, and facilitation of tumor migration via upregulation of matrix metalloproteinase-9 (MMP-9) [20].