SPP1 and metastatic malignant neoplasm in the lymph nodes: Moreover, results of univariate Cox regression analysis identified that TNM stage (p = 1.00e-08), invasion depth (p = 2.01e-06), distant metastasis (p = 0.035), lymph node metastasis (p = 6.47e-08) and SPP1 expression (p = 4.13e-04) were significant prognostic factors that influence on the OS of LUAD patients (Fig. 2C).