ALK and lung adenocarcinoma: Epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) and echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase fusion tyrosine kinase inhibitor (EML4-ALK-TKI) exert substantial therapeutic effects in lung adenocarcinomas with specific commonly occurring mutations [2–5].