Even if CCL2 is believed to be the major recruiter of TAMs in gliomas [15,16,41,42], other factors like CX3CL1 [43], CXCL12, M-CSF and GM-CSF [44] can mobilize TAMs into brain tumor areas, and become relevant under Ccr2-deficiency. Here, CXCL12 is linked to central nervous system cancer.