The gene expression of CCR1 receptor and its ligand was strongly upregulated in microglia exposed to glioma conditioned medium probably mediated by CSF-1R signaling, including CCL3/5/6/9,especially CCL3.However, the current study proposes that the CCR1 signaling axis may not be a major factor in microglia chemotaxis (96). This evidence concerns the gene CCL3 and glioma.