MET and cancer: CD44 can directly potentiate receptor tyrosine kinase (RTKs) signalling pathways and act as a coreceptor for several growth factors, such as tyrosine-protein kinase Met (c-Met), vascular endothelial growth factor receptor-2 (VEGFR-2) and epidermal growth factor receptor (EGFR), thus enhancing cancer cell proliferation and correlating with poor prognosis and metastatic potential [119].