CXCR4 and colorectal carcinoma: C-X-C motif chemokine receptor 4 (CXCR4)-overexpressing CRC cells deliver multiple miRNAs (miR-25-3p, miR-130b-3p and miR-425-5p) to macrophages via sEVs, causing M2 polarization of macrophages via the PTEN/PI3K/Akt signaling pathway.