Expression patterns of β-catenin in in situ and invasive breast cancer

Background: beta -Catenin plays a central role in the E-cadherin/catenin cell-cell adhesion complex and is possibly involved in cellular signalling pathways. In this study, we evaluated the expression patterns of this molecule in in situ and invasive breast cancer. Methods: The expression of beta -catenin was evaluated in 121 breast cancer specimens by immunohistochemistry. Its relationship to clinicopathological features was also investigated. Results: Altered beta -catenin expression was found in 68% of tumours. Lobular carcinomas showed abnormal beta -catenin expression more frequently (77%) than ductal carcinomas (64%) with 46% of lobular cases showing complete absence of beta -catenin immunoreactivity. Cytoplasmic beta -catenin localization was seen only in ductal carcinomas. Aberrant beta -catenin expression was observed in 54% of ductal carcinomas in situ with highly concordant. beta -catenin expression patterns in the nearby in situ and invasive components. Conclusions: Quantitative and qualitative changes in beta -catenin expression occur in a considerable proportion of in situ and invasive ductal carcinomas and are more prominent in invasive lobular carcinomas. (C) 2001 Harcourt Publishers Ltd.