Intratumoral c-Met expression is associated with vascular endothelial growth factor C expression, lymphangiogenesis, and lymph node metastasis in oral squamous cell carcinoma: implications for use as a prognostic marker

Hepatocyte growth factor has been identified as a lymphangiogenic factor in experimental animal models. However, the correlation between hepatocyte growth factor or c-Met expression and lymphangiogenesis in human spontaneous tumors has been rarely reported, and the distribution pattern of c-Met on tumor-related lymphatic vessels remains to be further investigated. Lymphatic vessel density, lymphatic invasion, the expression of hepatocyte growth factor, c-Met, and vascular endothelial growth factor C proteins were evaluated by immunohistochemistry in 76 cases of oral squamous cell carcinoma. The distribution of c-Met on lymphatic endothelium was examined. High expression of c-Met in tumor cells was significantly associated with advanced clinical stage (P = .045), high expression of vascular endothelial growth factor-C (P < .001), higher peritumoral lymphatic vessel density (P = .003), higher incidence of peritumoral lymphatic invasion (P = .032), and positive lymph node status (P = .005), in spite of its negative expression on most lymphatic vessels. Patients with high c-Met expression tumors exhibited shorter overall survival and disease-free survival (P < .001 and P = .010, respectively). Taken together, our results provide indirect evidence for an association and possible regulatory link of c-Met with the lymphangiogenic factor, vascular endothelial growth factor C, and, by extension, with lymphangiogenesis and lymph node metastasis, suggesting important prognostic significance of c-Met for patients with oral squamous cell carcinoma. (C) 2011 Elsevier Inc. All rights reserved.