RESEARCH COMMUNICATION Expression and Prognostic Value of Matrix Metalloproteinase-7 in Colorectal Cancer

Colorectal cancer (CRC) is one of the most frequent cancers in the world. According to the statistical data from International Agency for Research on Cancer (IARC), in 2008, 1.24 million new cases of colorectal cancer were clinically diagnosed, and this type of cancer killed 610,000 people. Now CRC is the fourth most common malignant tumor and the third leading cause of cancer death in both men and women in China (Long et al., 2011). Matrix metalloproteinase-7 (MMP-7), also known as matrilysin, is the smallest member of matrix-degrading metalloproteinases (MMPs) which play important role in degradation of extracellular matrix (ECM). It is specifically expressed in epithelial tumor cells instead of interstitial cells and is associated with cancer progression (Matthew et al., 2003). The components of ECM including collagen fibers, elastin, laminin, gelatin and proteoglycan are substrates of MMP-7. Because the proteolysis of ECM is essential for the occurrence, development and progression of cancer, MMP-7 expression plays a crucial role at early stage of tumor invasion and metastasis. In early invasive colorectal carcinomas, MMP-7 expression was significantly and independently associated with distant metastasis or adverse outcome through multivariate logistic regression analysis (Masaki et al., 2001). MMP-7 is also highly expressed in early stage of pancreatic cancer (Crawford et al., 2002). Further more, tumorigenesis is a multistep process involving cell growth, invasion, metastasis, and angiogenesis. MMP-7 has been shown