Research progress of HGF/MET signaling pathway in EGFR-TKI resistance 
in non-small cell lung cancer

Lung cancer is one of the most common malignant tumors of the world, and non-small cell lung cancer (NSCLC) makes up about 80%. The hepatocyte growth factor (HGF)/mesenchymal-epithelial transition factor (MET) signal pathway has pleiotropic effects on many biological processes. However, aberrant HGF/MET signal pathway activation has been observed in many tumor types, and promotes cellular proliferation and metastasis via growth factor receptors and other oncogenic receptor pathways. In recent years, aberrant HGF/MET signal pathway activation has been considered a key step of resistance to epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) therapy. This review addresses how aberrant HGF/MET signal pathway activation being associated with drug resistance to EGFR-TKI therapy in NSCLC patients.