Somatic mutations in MEK1 gene that affect the MAPK/ERK pathway were described in <1 % of non-small cell lung cancer (NSCLC) and they are more commonly reported in adenocarcinoma than squamous cell carcinoma, smokers or former smokers, and their presence was not associated with age, gender, race or disease stage [2, 7–10]. The gene discussed is MAP2K1; the disease is adenocarcinoma.