Overexpression of matrix metalloproteinase-7 (MMP-7) correlates with tumor proliferation, and a poor prognosis in non-small cell lung cancer

BACKGROUND: Matrix metalloporteinase-7 (MMP-7) is a member of the MMP family, and it has been reported to play an important role in tumorigenesis, invasion and metastasis. We performed a retrospective study on the MMP-7 expression in non-small cell lung cancer (NSCLC) according to the clinical characteristics, biological markers and the Wnt1 expression. PATIENTS AND METHODS: One hundred forty-seven postsurgical NSCLC patients were investigated. Immunohistochemistry was performed to evaluate the MMP-7 expression, the Ki-67 proliferation index, tumor angiogenesis and the Wnt1 expression. The TUNEL method was performed to investigate tumor apoptosis. RESULTS: Seventy-six carcinomas (51.7%) were MMP-7-positive. The MMP-7 expression was significantly higher in squamous cell carcinomas than in adenocarcinomas (P<0.0001). The Ki-67 proliferation index was significantly higher in MMP-7-positvie tumors than in MMP-7-negative tumors (P=0.0003). However, there was no difference in the MMP-7 expression in relation to apoptosis or angiogenesis. Regarding its regulation, the MMP-7 expression significantly correlated with the Wnt1 expression (r=0.426, P<0.0001). The overall survival was significantly lower in patients with MMP-7-positive NSCLCs than in those with MMP-7-negative NSCLCs (P=0.0018). A Cox regression analyses also demonstrated MMP-7 status to be a significant prognostic factor (hazard ratio, 2.187; P=0.0023). CONCLUSIONS: The overexpression of MMP-7 was associated with tumor proliferation, and a poor prognosis in NSCLCs. In addition, Wnt1 may play a critical role in regulating the intratumoral MMP-7 expression.