ALK and non-small cell lung carcinoma: A total of 6950 patients were included in the 27 studies, among which 24 (5130 cases) estimated the association of fusion of the EML4-ALK gene in NSCLC with a history of smoking; while 17 studies emphasized the association of the EML4-ALK rearrangement to tissue types (3360 cases); 13 papers reflected the relation of the EML4-ALK fusion gene to clinical stages (2876 cases) and 26 researches showed the association of this fusion gene and the gender of patients (5797 cases).