Cyclooxygenase-2 Is Involved In The Early Stages Of Colorectal Adenomatous Polyp Tumorigenesis

Objective: Cyclooxygenase (COX)is the critical enzyme of the synthesis of the prostaglandin and thromboxane. There are at least three isozyme: COX-1, COX-2, COX-3. COX-2 seldom expressed in normal tissue, but it can be induced by many kinds of inflammatory factors. In this article, immunohistochemical analysis, quantity mRNA and western blot were used to study the relationship between the COX-2 and colorectal adenomatous polyp.Materials and Methods:1.Grouping the study objectives:According to the Japanese Society for Cancer of the Colon and Rectum(JSCCR), A total of 61 colorectal polyps were divided into four groups. These included 33 low-grade adenomas (LGAs), 28 high-grade adenomas (HGAs) .23 normal tissue also examined.2. Examination method:Immunohistochemical was performed by mouse monoclonal anti-human antibody against COX-2 .The COX-2 mRNA expression level was determined by quantitative PCR. Western blotting was also used to examine the amount of COX-2.3. Statistical Analysis:All statistical analyses were performed using the Statistical Package for the Social Sciences (SPSS) 10.0. The association of variables was evaluated using theχ2 test. Differences were considered significant when p was less than 0.05.Results:COX-2 was expressed in neoplastic epithelial cells that weredistributed mainly in the superficial areas of polyps. COX-2 labeling indices (LIs) were 8.2% in LGAs, 6.3% in HGAs . mRNA and protein analysis also show that the expression of COX-2 in LGAs and HGAs higher than normal cellsConclusion:The results show that COX-2 might be involved in early stages of colorectal tumorigenesis. Colorectal adenomas could be a target for the chemopreventive strategy.