PURPOSE: The aim of this study was to analyse expression of COX-2, VEGF, CD34 and MMP-9 in colonic adenocarcinoma, and correlate this expression with clinicopathologic parameters. METHODS: Tumor sections of 66 consecutive patients undergoing potentially curative surgery for an adenocarcinoma of the colon were immunohistochemically stained using antihuman-COX-2, VEGF, CD34 and MMP-9 antibodies. For the evaluation of COX-2, VEGF and MMP-2 expression, those cases showing the respective antigen expression in more than 10% of the tumor cells were considered to be positive. Microvessel density (MVD) by CD34 expression was evaluated as the number of vessels per high-power field(X200). The mean value for the three fields were recorded as the MVD for each tumor. RESULTS: Although COX-2 expression was not correlated with any clinicopathologic factors, it showed the increased expression according to T-stage, lymph node metastasis and clinical staging. Microvessel density with CD34 expression was correlated with lymph node metastasis and clinical staging. MMP-9 expression was correlated with clinical stage. Microvessel density was correlated with COX-2, VEGF and MMP-9 expression. CONCLUSION: This results indicate that angiogenesis is a complex process that involves multiple factors including COX-2, VEGF, CD34 & MMP-9, and suggest that microvessel density with COX-2 and MMP-9 expression are related to tumor progression and metastasis of colonic adenocarcinoma.