MET expression plays differing roles in non-small-cell lung cancer patients with or without EGFR mutation

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors and Met inhibitors have enabled progress in the management of advanced non-small-cell lung cancer (NSCLC). However, the clinical benefits of these agents are not uniform across the NSCLC spectrum. Thus, we evaluated the prognostic effect of mesenchymal-epithelial transition (MET) expression in Asian NSCLC patients with or without EGFR mutation.

Frozen tumor tissues were collected from 92 patients with surgical resection and 10 with lymph node biopsy. Mutations in exons 18-21 in the EGFR-tyrosine kinase domain and MET expression were analyzed by using sequencing and immunohistochemistry, respectively.

The MET overexpression rate was 51% in NSCLC patients. MET-positive patients had poorer overall survival than MET-negative patients (29.8 versus 69.1 months, χ = 7.420, p = 0.006) in patients with wild-type EGFR. However, no statistically significant difference was found in EGFR mutant patients (35.0 versus 35.9 months, χ = 0.114, p = 0.735). Multivariate analysis showed that stage, MET expression, and sex were independent prognostic factors in patients with wild-type EGFR (χ = 32.896, p < 0.001).

These results suggest that MET expression has different prognostic significance in patients with differing EGFR mutation status. Whether MET inhibitors should be given early to NSCLC patients with EGFR wild-type needs further investigation.