Cellular-mesenchymal-epithelial transition (MET) protein has recently been identified as a novel target that shows promise for the treatment of non-small-cell lung cancer (NSCLC). However, the relationship between de novo MET expression and patient outcomes remains unclear.
We reviewed the data of patients who had been diagnosed with NSCLC between December 2013 and October 2014. All the patients were evaluated for MET expression status. MET-positive was defined as having an H-score ≥60 by immunohistochemistry analysis. MET expression was analyzed in 158 patients who were negative for the common driver genes, including EGFR, ALK, KRAS and ROS1. A chi-squared test was used to assess the clinicopathological parameters. Multivariate analyses were performed using the Cox proportional hazards model.
MET data were available for analysis in 158 advanced NSCLC patients. Of these, based on the MET H-score criteria, the IHC-positive rate was 48.1% (76/158). There were more patients with adenocarcinoma in the MET-positive group compared with the MET-negative group (P = 0.01). Nine patients with lymphoepithelioma-like carcinoma had no MET expression. There was no significant difference in overall survival (OS) between MET-positive and -negative patients. There was also no significant difference in the efficacy (Z = −0.44, P = 0.66) or progression free survival (PFS) of first-line chemotherapy between the MET-positive and -negative patients (mPFS 6.8 months [95% CI: 5.4-8.2] vs. 5.9 months [5.5-6.3], P =0.92).
Our data showed that de novo MET expression was not rare. It was not a predictive or prognostic factor for stage IV NSCLC patients, but this should be confirmed in larger population cohort.
Clinical trial identification
All authors have declared no conflicts of interest.