EML4 and lung adenocarcinoma: Eighty-three patients with pleural invasion of lung adenocarcinoma with EGFR mutation-positive were screened, and 9 types of EGFR mutation were detected, including: 18 g719 × (1 case, 1.20%), 19-DEL (36 cases, 43.37%), 19 deletions combined with EML4-ALK (1 case, 1.20%), 20 exon insertion (1 case, 1.20%), 21 L858R (38 cases, 45.78%), 21 L858R combined with MET exon 14 (1 case, 1.20%), 21 L858R combined with 20 S768I (2 cases, 2.41%), 21 L858R combined with 20 T790M (1 case, 1.20%), 21 L861Q (2 cases, 2.41%).