Erlotinib had a better response rate and fewer side effects than conventional chemotherapy in treating patients with EGFR mutant metastatic lung adenocarcinoma.7, 8, 9, 10 K‐ras mutation is frequent in patients with lung adenocarcinoma (15%‐30%), but there is still no approved effective target therapy for K‐ras mutant metastatic lung adenocarcinoma.10, 11, 12. This evidence concerns the gene KRAS and lung adenocarcinoma.