CCL2 and central nervous system cancer: In addition, C-C motif chemokine 2 (CCL2), colony-stimulating factor 1 (CSF-1), CX3CL1, and EGF secreted by glioma cells can promote the recruitment of TAMs and promote the transformation of the M2-type and lead to an immunosuppressive tumor microenvironment, further promoting the growth of glioma cells.