Mesenchymal-epithelial transition factor (MET) receptor, also known as c-Met or HGFR. MET is a transmembrane receptor tyrosine kinase that, upon binding its ligand HGF, activates intracellular signaling cascades (primarily the PI3K/Akt and MAPK pathways) that regulate cell growth, survival, motility, and invasion. In many cancers—including non-small cell lung cancer (NSCLC), gastric cancer, and hepatocellular carcinoma—MET signaling can become pathologically activated through gene amplification, protein overexpression, or specific mutations. This aberrant activation drives tumor progression, metastasis, and resistance to other targeted therapies (e.g., EGFR inhibitors).