In NSCLC patients harboring EGFR mutation, EGFR-tyrosine kinase inhibitors (TKIs) can improve quality of life, progression-free survival (PFS), and overall survival (OS).9 Several clinical parameters have been shown to affect the efficacy of EGFR-TKIs, including major mutation type, adenocarcinoma histology, tumor burden, Eastern Cooperative Oncology Group (ECOG) performance status (PS), baseline carcinoembryonic antigen (CEA) level, and lymphocyte-to-monocyte ratio.10–17. This evidence concerns the gene CEACAM5 and adenocarcinoma.