Towards uncovering such genetic determinants of treatment resistance, we performed next-generation sequencing (NGS)-based mutation profiling of lung adenocarcinomas with the EGFR L858R mutation from patients who received EGFR-TKI therapy, and searched for genetic variants/mutations that could differentiate patients displaying primary resistance to EGFR-TKIs from those having a durable response. This evidence concerns the gene EGFR and lung adenocarcinoma.