Subsequently, as shown in Table 4, the univariate COX analysis revealed that the prognosis of GC patients were associated with lymph node metastasis (P = 0.004), tumor differentiation (P = 0.034) and tumor Apelin expression (P = 0.002), but not with serum Apelin level (P = 0.332). This evidence concerns the gene APLN and metastatic malignant neoplasm in the lymph nodes.