GDNF and central nervous system cancer: On the other hand, glioma-cells release chemoattractant molecules that recruit TAMs and promote tumor growth: CCL2 [49], CCL7 (or MCP-3) [70], IL-33 [71], GDNF (Glial cell line-derived neurotrophic factor) [72], MCP-1 (CCL2), SDF-1 (CXCL12), CSF-1 (M-CSF), GM-CSF, and EGF [11].