MMP13 and metastatic malignant neoplasm in the lymph nodes: To gain further insight into the prognostic value of the biologic and clinicopathologic significance of HIF-1α and MMP-13 in NPC, immunohistochemical staining analysis showed that MMP-13 and HIF-1α over-expression were correlated with the lymph node metastases, clinical stage and poor prognosis of patients with NPC (P < 0.05), but not with age, gender and T stage.