CXCL12 and colorectal carcinoma: CXCL12-activated CRC cells recruit macrophages to the invasive front of the tumor, and they induce their M2 polarization by transferring via exosomes a panel of miRNAs (including miR-25-3p, miR-130b-3p and miR-425-5p) that deplete PTEN transcripts and activate STAT6.