EGFR and adenocarcinoma: In the 322 cases with adenocarcinoma (Table 2), these EGFR mutations were more frequently found in female cases than in male cases (53.1 vs 33.5%, P=0.0004), in well-differentiated tumours than in moderately/poorly differentiated tumours (53.8 vs 36.4%, P=0.0014), and in patients who were never smokers than in patients who were smokers (57.4 vs 32.1%, P<0.0001).