Firstly, we evaluated the effect of erlotinib on total EGFR and HER2 protein levels in sensitive NSCLC cell lines (Calu-3, H322 and H292 cell lines carrying wild-type EGFR; PC9 and HCC827 carrying EGFR E746-A750del mutation) and in resistant cell lines (A549, H1299, H1703 and Calu-1 intrinsically resistant carrying wild-type EGFR; HCC827GR5 with MET amplification as mechanism of acquired resistance to TKI) [16]. This evidence concerns the gene ERBB2 and non-small cell lung carcinoma.