EGFR and squamous cell carcinoma: The diagnostic yield was higher in patients with adenocarcinoma (13.6%; 176 of 1,297) than in squamous cell carcinoma (5.9%; 21 of 354) (p = 0.001) and EGFR-mutant adenocarcinoma (17.5%; 85/487) than in EGFR wild-type adenocarcinoma (10.6%; 68/639) (p = 0.001).