Abstract: Abstract Objective: To investigate the relationship between the expression of vascular endothelial growth factor-C (VEGF-C), vascular endothelial growth factor receptor-3 (VEGFR-3) and lymphangiogenesis, lymph node metastasis in colorectal cancer. Methods: Fifty colorectal cancer tissues and twenty colorectal adenoma tissues were selected randomly, meanwhile twenty normal tissues were selected as negative control group. Immunohistochemistry was used to detect the expression of VEGF-C and VEGFR-3. Lymphatic vessel density(LVD) was evaluated with lymphatic endothelium-specific marker, lymphatic vessel endothelial hyaluronan receptor-1(LYVE-1). All specimens had complete clinicopathologic data. Results: The positive rates of VEGF-C and VEGFR-3 expression in colorectal cancer were 44% and 36%, respectively. However, VEGF-C and VEGFR-3 expression were not found in colorectal adenoma tissues and normal tissues. There were significant differences in expressions of VEGF-C and VEGFR-3 proteins between patients with and without lymph node matastasis (P<0.001). There were no significant differences between gender, age, TNM stage，Dukes stage, Broder stage, histological type and invasion depth in CRC(P>0.05). LVDs were significantly higher in VEGF-C-positive and VEGFR-3-positive tumors compared with VEGF-C-negative and VEGFR-3-negative tumors(P<0.001). Univariate analysis revealed that Broder stage, VEGF-C-positive and VEGFR-3- positive were predictive factors of lymph node metastasis((P=0.024, P＜0.001, P＜0.001). Multivariate analysis revealed that the independent factors associated with lymph node metastasis were VEGF-C and VEGFR-3(P=0.001, P=0.02). Conclusions: This study suggests that the expression of VEGF-C and VEGFR-3 contributed to lymphangiogenesis and lymph nodal metastasis in colorectal cancer. VEGF-C and VEGFR-3 may serve as a new target of biological therapy in colorectal cancer. Key Words colorectal cancer, VEGF-C, VEGFR-3, lymphangiogenesis, lymph node metastasis

Key words: colorectal cancer, VEGF-C, VEGFR-3, lymphangiogenesis, lymph node metastasis