Hepatocyte growth factor (HGF), also called scatter factor, is produced by mesenchymal cells and signals through the MET receptor tyrosine kinase on epithelial cells. HGF binding activates MET, which recruits GAB1 and GRB2 and activates the RAS-MAPK, PI3K-AKT, STAT3 and SRC pathways. HGF/MET signaling promotes cell proliferation, survival, motility and invasive growth, and is important in embryonic development, liver regeneration and wound healing. MET amplification and overactivation contribute to tumor growth, metastasis and resistance to targeted cancer therapies.