In this respect, we and others have identified by NGS analysis cases of advanced NSCLC with co-mutations in the EGFR gene differently affecting the treatment outcome, including cases showing no OR to erlotinib and co-existence at baseline of the L858R and the intrinsic erlotinib-resistant T790M EGFR-mutations [51]. This evidence concerns the gene EGFR and non-small cell lung carcinoma.