Coexpression of VEGF-C and Cox-2 in human colorectal cancer and its association with lymph node metastasis

Purpose: Several lines of experimental evidence indicated that over-expression of vascular endothelial growth factor-C and cyclooxygenase-2 genes promotes angiogenesis and lymphangiogenesis, both of which are essential for the growth and spreading of tumor cells. This study was designed to evaluate the coexpression of vascular endothelial growth factor-C and cyclooxygenase-2 in human colorectal carcinoma to determine their relationships and correlations with lymph node metastasis and prognosis. Methods: Tissue samples of primary tumors and metastatic lymph nodes from 150 patients undergoing intentionally curative surgical resections for colorectal adenocarcinoma were immunohistochemically examined for vascular endothelial growth factor-C, cyclooxygenase-2, and CD34 expressions. Then, we analyzed their relationships and correlations with clinicopathologic findings and patients' survival time. Results: The positivity rate of vascular endothelial growth factor-C and cyclooxygenase-2 in the primary tumor was 68 and 72.7 percent, respectively, and in the metastatic lymph nodes was 93.3 and 80 percent, respectively. A significant correlation was found between the expression scores of vascular endothelial growth factor-C and cyclooxygenase-2 (P < 0.0001), and both also were correlated to microvessels density and several clinicopathologic parameters, including primary tumor size, lymph node metastasis, lymphatic invasion, and TNM stage. Patients with vascular endothelial growth factor-C-positive and/or cyclooxygenase-2-positive tumors had a significant shorter survival time than those with negative tumors did. However, in a multivariate analysis, only cyclooxygenase-2 expression was recognized as an independent prognostic factor (P = 0.0412; relative risk ratio, 3.067; 95 percent confidence interval, 1.046-8.994). Conclusions: These data show that in human colorectal carcinoma, vascular endothelial growth factor-C and cyclooxygenase-2 are coexpressed and significantly associated with lymph node metastasis and prognosis.