Abstract: Objective : To investigate the expression of vascular endothelial growth factor (VEGF) and matrix metalloproteinase-9 (MMP-9) genes in colorectal carcinoma and to identify their significance in infiltration and metastasis. Methods : The level of VEGF and MMP-9 mRNA was detected with quantitative reverse transcription-polymerase chain reaction (QRT-PCR) in 30 pairs of samples containing tumor tissues (group 1) and tissues of the resection margin (group 2). Protein expression was detected with immunohistochemistry. Thesedata were statistically analyzed along with corresponding clinicopathologic data. Results : The mRNA transcription level of VEGF and MMP-9 in tumor tissues was significantly higher than in tissues of the resection margin(P<0.01). A significant difference was found in mRNA transcription levels for both genes among patients withtumors of different degrees of invasion and different Dukes stages. The mRNA transcription level of bothgenes was significantly different between patients with and without lymph node metastasis (P<0.01 or P<0.05). The positive rates of VEGF and MMP-9 protein expression in group 1 were 56.67% (17/30) and73.33% (22/30), respectively, significantly higher than those in group 2 (P<0.01). A significant difference wasfound in protein expression level among patients with tumors of different degrees of invasion and differentDukes stages. The protein expression level was significantly different between patients with and withoutlymph node metastasis (P<0.01 or P<0.05). In tumor tissues, the VEGF mRNA transcription and protein expression level was correlated with MMP-9 mRNA transcription and protein expression level (P<0.01). Conclusion : VEGF and MMP-9 genes play important roles in carcinogenesis. Elevated expression of VEGF andMMP-9 reflects the ability to infiltrate and metastasize. Therefore, VEGF and MMP-9 genes can be considered indices for invasion, metastasis and progression.