Overexpression of Matrix Metalloproteinase-21 is Associated with Poor Overall Survival of Patients with Colorectal Cancer

Introduction: Matrix metalloproteinase-21 (MMP-21) is a member of the MMP family, which is overexpressed in some solid tumors and is thought to enhance the tumor invasion and metastasis ability. The aim of the present study is to examine the MMP-21 expression in human colorectal cancer and normal colorectal tissue using tissue microarray technique and to determine its association with clinicopathological characteristics and prognostic value. Materials and Methods: Four array blocks including 256 cases of colorectal cancer and adjacent normal tissues were investigated by immunohistochemistry assay. Staining evaluation results were analyzed statistically in relation to various clinicopathological characters and overall survival. Results: High level of MMP-21 expression was detected in colorectal cancer, significantly more than in normal colorectal epithelial cells. In colorectal cancer, MMP-21 was significantly positively correlated with depth of invasion, lymph node metastasis, and distant metastasis. The overall survival rate was significantly lower for patients with MMP-21 positive than those with MMP-21 negative tumors. However, no correlations between MMP-21 expression and patients' age, sex tumor location, or differentiation status were detected. Conclusion: Our findings emphasize the important role of MMP-21 in the invasion and metastasis process in human colorectal cancer. It might also serve as a novel prognostic marker that is independent of, and additive to, the TNM staging system.