CXCL12 and neoplasm: Because mononuclear phagocytes express both CXCL12 GPCRs and HB-EGF, we argued that the recruitment of mononuclear phagocytes to a site of metastasis such as liver through CXCL12 should induce a release of HB-EGF, which is expected to activate HER1 and favour tumour progression.