Expression of VEGF‐C and VEGF‐D as Significant Markers for Assessment of Lymphangiogenesis and Lymph Node Metastasis in Non‐Small Cell Lung Cancer

Vascular endothelial growth factor (VEGF)‐C and VEGF‐D induce lymphangiogenesis through activation of VEGF receptor 3 (VEGFR‐3) and have been implicated in tumor spread to the lymphatic system. Lymph node dissemination critically determines clinical outcome and therapeutic options of patients with non‐small cell lung cancer (NSCLC). However, the relationship of VEGF‐C, VEGF‐D, and lymph node metastasis in cancers, including NSCLC, is still controversial. To evaluate the relationship between lymphangiogenesis and lymph node metastasis, the expression of VEGF‐C and VEGF‐D in NSCLC tumors were detected by immunohistochemistry and quantitative real‐time polymerase chain reaction (QRT‐PCR). QRT‐PCR revealed that in marginal region VEGF‐C and VEGF‐D mRNA was significantly higher than in tumor center, and VEGF‐D mRNA was also higher than that in peritumoral lung tissue. Immunohistochemically, we observed the same heterogeneous expression of VEGF‐C and VEGF‐D proteins. The group with high expression of VEGF‐C and VEGF‐D in marginal region had a higher incidence of lymph node metastasis compared with the group with low expression. Furthermore, the group with high expression of VEGF‐D in marginal region had a higher incidence of lymphatic invasion. The group with high peritumoral lymphatic vessel density (LVD) had higher expression of VEGF‐C and VEGF‐D mRNA compared with the group with low peritumoral LVD. Our studies suggested that the expression of VEGF‐C and VEGF‐D at invasive edge was significantly associated with lymph node metastasis or lymphatic invasion in patients with NSCLC and may be involved in regulation of lymphangiogenesis and lymph node metastasis in NSCLC. Anat Rec, 2010. © 2010 Wiley‐Liss, Inc.