Prognostic Significance of Abnormal beta - catenin Expression in Breast Carcinoma

ABSTRACT

BACKGROUND: The subcellular localization and activity of beta-catenin are tightly regulated within the cell. The aim of this study was to analyze the aberrant beta-catenin expression in breast carcinomas and to determine its clinical significance. METHODS: Fifty five cases of breast carcinoma were immunostained with monoclonal antibodies against beta-catenin. Normal expression of -catenin was defined as exclusive membranous staining. Abnormal expression of beta-catenin was reclassified into 3 categories: complete or partial loss of membranous staining (LOM) without cytoplasmic staining and nuclear staining, LOM with cytoplasmic staining and without nuclear staining, and LOM with nuclear staining and with/without cytoplasmic staining. RESULTS: Normal membranous beta-catenin expression was detected in 25 (45.5%) of 55 cases of breast carcinoma. Thirty cases with abnormal -catenin expression comprised 9 cases (16.1%) showing LOM without cytoplasmic and/or nuclear staining, 20 cases (36.4%) showing LOM with cytoplasmic staining and without nuclear staining, and one case (1.8%) showing LOM with nuclear and cytoplasmic staining. Abnormal beta-catenin expression was significantly correlated with lymph node metastasis (p=0.03). LOM with cytoplasmic and/or nuclear expression was significantly correlated with poor disease free survival by univariate (p=0.03) and multivariate analyses (p=0.03). In addition, it was correlated with poor overall survival with a borderline significance (p=0.059). CONCLUSIONS: This study suggests that the cytoplasmic and/or nuclear expression of beta-catenin can be used as a biologic marker for predicting disease recurrence and poor patients' survival in breast carcinomas.