Hattori et al.[14] believe that tumor diameter, pure solid, pleural involvement, presence of an air bronchogram sign on radiography, high CEA level (>5 ng/mL), and high maximum standardized uptake value (SUVmax) on positron emission tomography (PET) (>5) are important predictors of lymph node metastasis for clinical stage IA lung adenocarcinomas. This evidence concerns the gene CEACAM5 and metastatic malignant neoplasm in the lymph nodes.