Figure 3.

Contribution of glioblastoma-associated microglia and macrophages to tumor progression. TAMs have bimodal, yin and yang effects on immune responses. The yin and yang microglia/macrophage subtypes refer to M2- and M1-like respectively. M1-like TAMs are relative with the pro-inflammatory property while M2-like TAMs are relative with the anti-inflammatory property. The polarization of TAMs from M1 to M2 phenotype is associated with the tumor progression. TAMs are believed to promote GBM progression by several pro-tumorigenic activities including: 1) promoting GBM cells proliferation; 2) promoting GBM cells migration and invasion; 3) promoting angiogenesis in GBM; 4) facilitating extracellular matrix (ECM) degradation; 5) facilitating the immunosuppressive TME.