OBJECTIVETo investigate the expression of beta-catenin and its significance in colorectal neoplasms.

METHODSTissue specimens of normal colorectal mucosa, mucosa adjacent to carcinoma, colorectal adenoma and adenocarcinoma were examined for beta-catenin with immunohistochemistry.

RESULTSBeta-catenin was mainly expressed in the cytomembrane of normal mucosa and mucosa adjacent to cancer (the positive rates were 94.6% and 86.5%, respectively) and also in the cytoplasm (the positive rates were 38.7% and 55.0%, respectively), while its expression was negative in the cell nucleus. In adenoma and adenocarcinoma, beta-catenin was mainly expressed in the cytoplasm (the positive rates were 85.1%,and 93.7%, respectively) and partially in the cell nucleus (the positive rates were 12.8% and 23.4%, respectively). Compared with normal mucosa and mucosa adjacent to cancer, the expression of beta- catenin in the cytomembrane of adenoma and adenocarcinoma was significantly lower (P<0.05), while its expression in the cytoplasm and cell nucleus of adenoma and adenocarcinoma was significantly higher (P<0.05). The positive rates of cytoplasm in highly-and moderately differentiated adenocarcinoma were significantly higher than that in poorly-differentiated adenocarcinoma (the positive rates were 100%, 95.5% and 68.8%, respectively). Beta-catenin expression rate in cytoplasm was correlated with Dukes'stages of adenocarcinoma, which was significantly lower in stage A than in stage B/C.

CONCLUSIONThe expression of beta-catenin is significantly correlated with differentiation and Dukes'stages of colorectal carcinoma and it can be used as an indicator for the prognosis of colorectal carcinoma.