EGFR mutation is positively correlated with C-Met protein expression: a study of 446 resected lung adenocarcinoma

Background: Epidermal growth factor receptor (EGFR) mutation and mesenchymal-epithelial transition factor (C-Met) amplification are known factors for primary resistance to EGFR tyrosine kinase inhibitors (EGFR-TKIs) in advanced primary lung adenocarcinoma. However, little is known about the relationship between high expression of C-Met protein and primary EGFR mutation. This research aims to investigate the correlation between EGFR mutation and C-Met protein expression in resected primary lung adenocarcinoma.

Methods: Four hundred and forty-six surgically resected lung adenocarcinoma between 2013-2015 were collected for EGFR mutation analysis by real-time PCR (RT-PCR) and C-Met protein expression by immunohistochemistry (IHC). The relationship between the two biomarkers and clinicopathological features were analyzed.

Results: The positive rate of EGFR mutation and C-Met protein expression were 66.4% (296/446) and 96.4% (430/446). EGFR mutation was significantly higher in female, mild to moderate differentiation, lepidic, acinar and papillary histological subtypes (P<0.05). C-Met expression was more prominent in female than male (201 vs. 123, 45.07% vs. 27.57%). EGFR mutation was found positively correlated with C-Met protein expression (P<0.05).

Conclusions: EGFR mutation and C-Met protein expression are prone to have a female predominance, and are positively correlated with each other in surgically resected lung adenocarcinoma specimens. This finding may be beneficial in explaining some of the resistance mechanisms of EGFR-mutated cases, which is worth further study.