Sonic Hedgehog Expression in Colorectal Neoplasms

ABSTRACT

BACKGROUND/AIMS: Dysregulation of the hedgehog pathway has been implicated in regeneration and carcinogenesis, leading to the expression of the sonic hedgehog (Shh) protein in gastrointestinal neoplasms. The expression of Shh in colon neoplasms and paired normal colonic mucosa was therefore investigated. METHODS: Forty-four colon cancers and 73 colon adenomas that were removed by surgical colectomy or colon polypectomy between August 2005 and August 2006 were included. Colorectal neoplasms and the adjacent normal colon tissue were examined by immunohistochemistry using rabbit polyclonal Shh antibody. RESULTS: Expression of Shh was up-regulated in adenomas and adenocarcinomas of the colon compared to normal colon tissues (p<0.001). The degree of Shh expression was not associated with the size, shape, or, location of the tumor, or as the age and gender of the patient. In normal colonic epithelium, Shh was expressed at the apex of the crypts and in a few basally-located cells. CONCLUSIONS: Higher levels of Shh expression in colonic adenoma and adenocarcinoma suggest that Shh is required during epithelial proliferation in the colon. Hedgehog signaling is likely to be associated with early tumorigenesis in colonic neoplasms.