MMP9 and metastatic malignant neoplasm in the lymph nodes: In addition, the serum concentration of MMP-9 protein in patients with an advanced TNM stage (511.42±251.52), and lymph node metastasis (498.55±265.77) was significantly higher than that in the patients at an early TNM stage (305.22±223.99) and exhibiting no lymph node metastasis (300.30±205.62), respectively (P<0.01).