MET is activated by auto-phosphorylation when bound by HGF [152,153,154] engaging several downstream signaling networks, including the PI3K/AKT/mTOR, phospholipase C (PLC), and RAS/MAPK/RAF/ERK pathways involved in tumor growth and invasion [154,155,156,157] (Figure 3). The gene discussed is HGF; the disease is neoplasm.