Analyses of the mdig expression levels and the patient survival data clearly suggest that increased expression of mdig predicts poorer overall survival (OS) of the total lung cancer patients (Fig. 5A) and the poorer OS of the lung cancer patients without lymph node metastasis or only having possible proximal lymph node metastasis (Figs. 5B and 5C). This evidence concerns the gene RIOX2 and metastatic malignant neoplasm in the lymph nodes.