Figure 3.

Immunosuppressive effects of tumor microenvironment (TME). Tumor cells secrete a number of chemokines and cytokines that inhibit immune cell population, including dendritic cell (DC) and T cells. The inhibition of DC for taking up and presenting tumor antigen may cause immune ignorance. Tumor cells also recruit and generate immunosuppressive cells, such as regulatory T cells (Tregs), myeloid-derived suppressor cells (MDSCs), tumor-associated macrophages (TAMs), and tumor-associated neutrophils, forming an immunosuppressive network that protects tumors from anti-tumor immune response, which leads to a condition called immune tolerance (modified from the presentation of Daniel W. Sharp et al. [69]).