Given the increasing changes in attitude toward the risks of exposure to cigarette smoking and increasing air pollution, the prevalence of lung squamous cell carcinoma cases has declined; lung adenocarcinoma (LUAD) became the most common lung cancer in 1998–2002 (Lortet-Tieulent et al., 2014; Travis et al., 2015). Cancer incidence and mortality can be reduced by population screening, but LUAD is often diagnosed at advanced stages with disseminated metastatic tumors. Advanced LUAD are inoperable and highly resistant tumors to chemotherapy and irradiation. Despite the emerging improvements in chemoradiotherapy, targeted therapy, and immunotherapy, the 5-year survival rates remain low (7–20%), and recurrence rates remain high at 30–50% (Miyata et al., 2015). With limited effective therapeutic options in LUAD, identification of novel targets for therapy is sorely needed.
