C-MET is a coding product of proto oncogene c-MET, hepatocyte growth factor (HGF) receptor with tyrosine kinase activity.The abnormal expression of c-Met gene is correlated with the tumorigenesis and development of lung cancer.Once the tyrosine kinase is activated by the interaction between the HGF ligand and the TK receptor, and the activated kinase will promote the cell proliferation, angiogenesis, invasion and metastasis of different tumors, as well as lung cancer. Here, HGF is linked to lung cancer.