ALK and neoplasm: However, like most retrospective studies of rare genes, our study has some limitations including observational assessment of tumor recurrence, unknown EGFR or KRAS status, and a short follow-up time, Therefore, in a future study, we will obtain treatment information after tumor recurrences, analyze other rare genes, and also analyze the relationship of the solid predominant with mucin production and invasive mucinous adenocarcinoma subtypes with ALK rearrangement and treatment outcome.