BACKGROUND: The surface pit pattern of early stage colorectal cancer changes with tumor growth and invasion. It was postulated by us that the expression of matrix metalloproteinase-7 is related to tumor invasiveness and disturbance of the pit pattern. METHODS: Sixty-eight colorectal epithelial tumors were examined, and the pit pattern was classified by stereoscopic microscopy. Immunostaining for matrix metalloproteinase-7 and its substrate laminin were performed. RESULTS: The rate of matrix metalloproteinase-7 positive staining was significantly higher for mucosal (70.6%) and submucosal cancer (80.0%) than for adenoma (18.6%) (p<0.0083). The rate of matrix metalloproteinase-7 positive specimens was significantly higher for type IV and type V compared with type III pit patterns. Where the tumor surface was positive for matrix metalloproteinase-7, expression of laminin was negative in 40% of specimens with a type IV pit pattern and 100% of those with the type V pit pattern. CONCLUSIONS: The results of this study indicate that expression of matrix metalloproteinase-7 is related to both the invasiveness of colorectal epithelial tumors and the disturbance of the pit pattern on the tumor surface.
BACKGROUND: The surface pit pattern of early stage colorectal cancer changes with tumor growth and invasion. It was postulated by us that the expression of matrix metalloproteinase-7 is related to tumor invasiveness and disturbance of the pit pattern. METHODS: Sixty-eight colorectal epithelial tumors were examined, and the pit pattern was classified by stereoscopic microscopy. Immunostaining for matrix metalloproteinase-7 and its substrate laminin were performed. RESULTS: The rate of matrix metalloproteinase-7 positive staining was significantly higher for mucosal (70.6%) and submucosal cancer (80.0%) than for adenoma (18.6%) (p<0.0083). The rate of matrix metalloproteinase-7 positive specimens was significantly higher for type IV and type V compared with type III pit patterns. Where the tumor surface was positive for matrix metalloproteinase-7, expression of laminin was negative in 40% of specimens with a type IV pit pattern and 100% of those with the type V pit pattern. CONCLUSIONS: The results of this study indicate that expression of matrix metalloproteinase-7 is related to both the invasiveness of colorectal epithelial tumors and the disturbance of the pit pattern on the tumor surface.