MET and phosphorylated MET as potential biomarkers in lung cancer.

This study aimed to investigate the expression and prognostic role of the receptor tyrosine kinase MET, phosphorylated MET, and the ligand hepatocyte growth factor (HGF) in patients with lung cancer. This retrospective study included 129 patients with non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC) with available tumor tissue and survival data. MET, pMET, and HGF expression were assessed using immunohistochemistry. MET, pMET, and HGF were more highly expressed in tumor tissue when compared to the adjacent lung parenchyma. A specific localization pattern was also evident: membranous, cytoplasmic, and nuclear patterns of expression were seen for MET, pMET, and HGF. In addition, high expression of two specific forms of phosphorylated MET--cytoplasmic expression of Y1003 and nuclear expression of Y1365--appeared to correlate with a worse overall survival (P = .016; hazard ratio [HR], 1.86; 95% confidence interval [95% CI], 1.12- 3.07; and P = .034; HR, 1.70; 95% CI, 1.04-2.78, respectively). In summary, MET, pMET, and HGF are highly expressed in both NSCLC and SCLC. Specific forms of pMET may serve as potential biomarkers in lung cancer.