KRAS hotspot mutations were significantly more common in current and previous smokers than in never-smokers (33% versus 14%; p=0.015), patients with adenocarcinoma than in those with squamous cell carcinoma (32% versus 14%; p=0.031), patients who had prior surgery for tumor resection than those who did not (38% versus 22%; p=0.029), and patients who had prior EGFR inhibition than in those who did not (35% versus 19%; p=0.021). This evidence concerns the gene EGFR and squamous cell carcinoma.