GDNF and glioblastoma: Since GBM-derived chemokines such as GDNF (glial cell-derived neurotrophic factor), GM-CSF (granulocyte-macrophage colony-stimulating factor), and CCL2 (chemokine ligand), have been proven to be involved in TAM recruitment and polarization17, classical methods are to deplete TAMs and reshape TAM population by targeting these molecules18 (Table 1).