Previous retrospective literature indicated that ALK positiveness is more common in young and never smoking or light smoking NSCLC patients [30], and ALK fusion gene mainly occurs in lung adenocarcinoma, which is extremely rare in lung squamous cell carcinoma or other histological types of NSCLC [31] [32].The results of our study are consistent with the above conclusions: the proportion of young, adenocarcinoma and never smoking patients is significantly higher, which reflects the specific population distribution characteristics of ALK fusion gene mutation. This evidence concerns the gene ALK and lung adenocarcinoma.