What's the role of beta-catenin in colorectal cancers?

Beta-catenin, a central molecule of the Wnt-signalling pathway was previously known to involve in the tumourigenesis of various gastrointestinal cancers such as gastric cancer and colon cancer. In colon cancer, previous studies suggested association between the feature of nuclear beta-catenin, which remarks an activation of the Wnt-signalling pathway, and poorer survival. However, a correlation between the overall expression of this protein and treatment outcome in colorectal cancer has not been clearly defined.

A research article published on 21 October 2008 in the World Journal of Gastroenterology addresses this interest. The researcher team from the Tumour Biology Research Group, Prince of Songkla University used immunohistochemical technique to study their tumour tissue from 163 cases of colorectal cancer. In their study, they invent a new parameter called 'overall staining density' which meant the density percentage of tumour cells that gave positive staining with beta-catenin. Unlike previous reports, the study did not find a predictive value of nuclear beta-catenin in CRC. Instead, the overall expression of beta-catenin in CRC showed an association with better differentiation and earlier staging. Moreover, the parameter also independently predicted superior survival. High overall staining density had inverse correlation with clinical staging, nodal status, metastatic status and differentiation. Multivariate analysis found that high overall staining density was independently associated with better survival.

The study indicated that role of beta-catenin in colorectal cancer may not be explained solely through the Wnt-signalling pathway. The protein may have an alternative role that is related to tumour cell differentiation and better prognosis.