AREG and colonic neoplasm: Singh and Coffey recently described a new extracrine (exosomal targeted receptor activation) signalling that involves the packaging and release of EGFR ligands via exosomes 19, and Coffey's group demonstrated that tumour exosomes, carrying the EGFR ligand AREG, are rapidly internalized in recipient human breast and colon cancer cells leading to cancer cell invasion 20.