The initiation and development of colorectal cancer is closely associated with the malignant transformation of colorectal polyps. The aim of this study was to analyze the expression of the bone morphogenetic protein-2 (BMP2), toll-like receptor 3 (TLR3), TLR4 and cyclooxygenase-2 (COX2) proteins in colorectal polyps, adenoma and adenocarcinoma. An immunohistochemical streptavidin-peroxidase (SP) method was used to examine the expression of MBP2, TLR4, TLR3 and COX2 in 20 colorectal juvenile polyps and 15 colorectal polyps of hamartomatous polyposis obtained from children, and 20 colorectal adenomas and 20 colorectal adenocarcinomas obtained from adults. A comparison of the expression levels of TLR3 among the groups revealed a gradual downward trend from the colorectal juvenile polyp group to the colorectal hamartomatous polyposis, adenoma and adenocarcinoma groups, respectively. The expression level of TLR3 was significantly lower in the colorectal adenocarcinoma group (p<0.05). The expression levels of TLR3, TLR4 and BMP2 were significantly different among the colorectal juvenile polyp, hamartomatous polyposis, adenoma and adenocarcinoma groups. These three protein molecules may be significant in the development and malignant transformation of colorectal polyps.
Keywords: colorectal juvenile polyp; colorectal hamartomatous polyposis; colorectal adenoma; colorectal adenocarcinoma; toll-like receptor 4.