Sonic hedgehog-Gli1 pathway in colorectal adenocarcinomas

AIM: To determine the role of Sonic hedgehog (Shh) pathway in colorectal adenocarcinomas through analysis of the expression of Shh pathway-related molecules, Shh, Ptch1, hedgehog-interacting protein (Hip), Gli1, Gli3 and PDGFR alpha. METHODS: Expression of Shh in 25 colorectal adenocarcinomas was detected by RT-PCR, in situ hybridization and immunohistochemistry. Expression of Ptch1 was observed by in situ hybridization and immunohistochemistry. Expression of Hip, Gli1, G13 and PDGFR alpha was analyzed by in situ hybridization. RESULTS: Expression of cytokeratin AE1/AE3 was observed in the cytoplasm of colorectal crypts. Members of the Hh signaling pathway were expressed in colorectal epithelium. Shh was expressed in cytoplasm of dysplastic epithelial cells, while expression of Ptch1, Hip and Gli1 were mainly detected in the malignant crypts of adenocarcinomas. In contrast, PDGFR alpha was expressed highly in aberrant crypts and moderately in the stroma. Expression of Gli3 could not be detected in colorectal adenocarcinomas. CONCLUSION:: These data suggest that Shh-Ptch1-Gli1 signaling pathway may play a role in the progression of colorectal tumor. (c) 2007 The WJG Press. All rights reserved.