Investigation of β-catenin and E-cadherin expression in Dukes B2 stage colorectal cancer with tissue microarray method. Is it a marker of metastatic potential in rectal cancer?

β-catenin and E cadherin are both membrane-associated proteins which are essential regulators and providers of cellular adhesion. In the metastatic cascade of malignant tumours, detachment of tumour cells from each other is a very important step. It has been shown in several tumour types, that reduced expression of these proteins is important. The aim of our study was to clarify the expression profile of these proteins, and correlate the findings with the metastasizing potential of early stage colon and rectal cancers. Formalin fixed and paraffin embedded samples from 79 Dukes B2 stage colorectal cancer were examined using a tissue microarray approach. The expression of β-catenin and E-cadherin proteins was determined immunohistochemically. Our findings indicated that there is a tendency for metastatic spread in cases when membranous expression of β-catenin is lost (p = 0.062). Similarly metastases in negative cases developed more rapidly, than in positive ones (p = 0.05). Survival rate was worse in the negative cases. The risk of metastasis in rectal cancer was significantly higher in the β-catenin membranously negative than positive groups (p = 0.024) and in case of β-catenin nuclear expression the risk was also higher (p = 0.047). Reduced E-cadherin expression also correlated with development of metastatic disease, but this association was statistically not significant. The immunohistochemical analysis of 79 cases shows that in Dukes B2 stage colorectal tumours clarification of β-catenin and E-cadherin expression patterns is reliable for predicting the metastatic potential of early stage rectal cancer and hence the method may have relevant implications in the therapeutic management of these cancers.