MET expression and copy number heterogeneity in nonsquamous non-small cell lung cancer (nsNSCLC)

[Mechanism of c-MET in Non-small Cell Lung Cancer and Its Treatment and Testing]

Hepatocyte growth factor/c-MET (HGF/c-MET) signaling pathway can be abnormal activated by many mechanisms such as c-MET mutation, amplification and the overexpression of HGF, and it plays an important role in the development of non-small cell lung cancer (NSCLC), as well as in the tolerance of epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) in NSCLC. Therefore, c-MET is a new molecular target for the therapy of NSCLC since EGFR and ALK. At present, although the c-MET inhibitors have shown a potential prospect in some clinical trials, its assessment of safety and effectiveness in clinical applications, and the choice of testing methods and standards still need a further discussion. In this paper, we summarized the mechanism of c-MET in NSCLC, as well as its treatment prospect and selection of testing methods.

Predictive and prognostic value of de novo MET expression in patients with advanced non-small-cell lung cancer

BACKGROUND

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.

METHODS

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.

RESULTS

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). In the cell model, the MET-positive cell showed no difference in chemotherapy but with a increase in percentage of growth inhibition upon treatment with MET inhibitor INC280 compared to MET-negative cell.

CONCLUSION

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.