Met is a receptor tyrosine kinase often expressed in epithelium. Its paracrine ligand, hepatocyte growth factor (“scatter factor”), is produced by stromal cells. Met signals via Ras, pi3k/Akt, and stat, affecting mitosis, survival, angiogenesis, migration, invasion, and as implied, mesenchymal–epithelial transversion. Upregulation in cancer cells results in “invasive growth.” Amplification of MET is documented in 4.1% of North American lung adenocarcinomas, but MET overexpression maybe more commonc. Mutations in MET occur rarely.