The Expression Of VEGF,MMP-2 And Their Correlations With Angiogenesis In Colorectal Carcinoma

Today colorectal carcinoma is one of the most common malignant tumors in the world.- The fact that no significant improvements exist in the overall outcome for patients with colorectal carcinoma over the last three decades is mainly due to it's recurrence and metastasis. Recent reports reveal that angiogenesis is nessessary for growth and metastasis in all solid tumors. Angiogenesis is regulated by certain stimulators and inhibitors. Vascular endothelial growth factor (VEGF) is a most typical mitogen of endothelial cells and a potent angiogenesis-promoting factor. It has been proved to be a crucial angiogenic factor in certain human tumors. Matrix metalloproteinase 2 (MMP-2) is a protease that cleaves specifically type IV collagen, the main structural component of the besetment membrane. In several human tumors, MMP-2 expression was correlated positively with invasion, metastasis and angiogenesis. Microvessl density (MVD) is a quantitative measure of angiogenesis and has been shown to be an important parameter of the biologicalbehavior of various malignant tumors. Recently, the angiogenesis activity of colorectal carcinoma and its regulators have not been well defined yet.Objective: This study evaluated the roles of VEGF, MMP-2 and angiogenesis in carcinogenesis and progression of colorectal carcinoma as well as their interaction in order to understand the mechanisms of carcinogenesis, progression and angiogenesis, so as to provide a theorectical foundation for potential new therapy method (anti-angiogenesis therapy) of colorectal carcinoma.Materials and methods: 51 cases of colorectal carcinoma samples, 18 cases of colorectal adenoma samples and 18 cases of normal colorectal mucosa samples were collected. All the tissues were fixed in 10% neutral formalin and embedded in paraffin. Immunohistochemical streptavidin peroxidase conjugate method was used to analyze the MVD as well as VEGF, MMP-2 expression in normal colorectal mucosa, colorectal adenoma and colorectal carcinoma. Statistical analysis was performed with SPSS 10.0 software, using t-test, ANOVA, Chi-square and Fisher's exact probability test. Statistically significant level was considered as "alpha eguals 0.05".Results:1 . Positive staining for VEGF protein was mainly observed in the cytoplasm and /or on the membrane of neoplastic cells as well as some vascular endothelial cells. There was no positive expression of VEGF in normal colorectal mucosa group. The VEGF-positive rates were 38.89% (7 of 18) in colorectal adenoma group and 64.71% (33 of 51) in colorectal carcinoma grouprespectively. The VEGF-positive rates in colorectal adenoma group and colorectal group were higher than that in normal mucosa group (P<0.05), but there was no significant difference between them. Positive staining for MMP-2 protein was mainly observed in the cytoplasm and /or on the membrane of neoplastic cells as well as some mesenchymal cells. There was no positive expression of MMP-2 in normal mucosa group. The MMP-2 -positive rates were 33.33% (6 of 18) in colorectal adenoma group and 54.98% (28 of 51) in colorectal carcinoma group respectively. The MMP-2 positive rates in colorectal adenoma group and colorectal carinoma group were higher than that in normal mucosa group (P<0.05), but there was no significant difference between them. The MVDs were 9.70±3.20 in normal colorectal mucosa group, 13.52±4.12 in colorectal adenoma group and 22.44±6.96 in colorectal group respectively. The difference between either two of them was significant (PO.05).2. In highly, moderately and poorly differentiated colorectal carcinomas, the positive rates of VEGF protein were 57.70% (15 of 26), 68.75% (11 of 16) and 77.78% (7 of 9) respectively, which tended to increase with the deterioration of tumor differentiation, but no significant difference of VEGF expression was founded among these groups (P>0.05). In highly, moderately and poorly differentiated colorectal carcinomas, the positive rates of MMP-2 protein were 42.31% (11 of 26), 68.75%( 11 of 16) and 66.67% (6 of...