Since CXCL12 is a classical ligand of CXCR4 [5] and CSF-1/CSF-1R crosstalk from prostate cancer cells to recruited macrophages was previously identified, we proposed that the feedback crosstalk from macrophages to cancer cells is partly mediated by CXCL12/CXCR4. This evidence concerns the gene CSF1 and prostate cancer.