EGFR and lung adenocarcinoma: Integrin β1 was expressed in all molecular subtypes of lung adenocarcinoma, though expression was lower in EGFR-mutated tumors (n = 17, mean 1.4 ± SD 0.7) relative to KRAS-mutated tumors (n = 40, mean 1.9 ± SD 0.8, P = 0.03) and all other tumors (n = 8, mean 2.1 ± SD 0.5, P = 0.04) (data not shown).