【Abstract】ObjectiveTo detect expressions of E-cadherin and α-catenin in breast cancer and analyze the relationship between those expressions and biological behaviors of breast cancer. MethodsFifty-four female patients with breast cancer received modified -radical -mastectomy or radical mastectomy in our department from August 1998 to March 1999. Their ages ranged from 30 years to 76 years and the postoperative follow-up time ranged from 6 to 67 months. Sixteen patients died during their follow-up time. The expressions of E-cadherin and α-catenin in specimens of 54 breast carcinomas and 21 normal breast tissues around tumor were measured by immunohistochemical method. Results In normal breast tissues, E-cadherin and α-catenin were expressed on cell membrance of ductal and acinic cells. No abnormal expressions were found in normal breast tissues. The abnormal expression rates of E-cadherin and α-catenin in breast cancer were 51.9% and 63.0% respectively. Abnormal expressions of E-cadherin and α-catenin were significantly correlated with histological grade and proliferative grade. Abnormal expression of α-catenin was significantly correlated with TNM staging, axillary lymph node metastasis and postoperative distant metastasis. Abnormal expression of Ecadherin was positively correlated with expression of HER-2. COX multiple factor analysis suggested that neither E-cadherin nor α-catenin expression was an independent prognostic indicator of breast cancer. ConclusionAbnormal expressions of E-cadherin and α-catenin frequently occur in breast cancer. Abnormal expressions of E-cadherin and α-catenin are correlated with disturbance of proliferation and differentiation of breast cancer and its metastasis.