Abstract: Objective: To investigate the expression of Ezrin and its significance in breast cancer.Methods:The Ezrin expressions in breast cancer tissue of 90 cases,adenosis tissue of 10 cases and breast intraductal papillary tumor tissue of 10 cases were detected by SP immunohistochemistry.Results:The strong positive expression rates of Ezrin in breast cancer tissue,adenosis tissue and breast intraductal papillary tumor tissue were 58.9%,10.0% and 20.0%,respectively,the differences of which were statistical significant(P 0.01).The expression level of Ezrin in cases with lymph node metastasis was higher than in whose without lymph node metastasis(P 0.01),and its expression differences in tumor size,TNM staging and age were not statistically significant (P0.05).The most expression position of Ezrin in breast cancer was in the cytoplasm(62.2%),part expression was in the membrane(22.0%) and cell membrane top(15.8%).The most expression position of Ezrin in adenosis tissue and breast intraductal papillary tumor tissue was in cell membrane top(7 /9 and 6 /9).The Ezrin expression differences of three groups were statistical significance(P0.01).The Ezrin expression in cell membrane top of breast cancer was related to the lymph node metastasis,differentiation stage and hormone receptor expression(P0.05 to P0.01).The Ezrin expression of in cytoplasm was related to the lymph node metastasis,high differentiation stage and hormone receptor negative expression(P0.05 to P0.01).The differences of Ezrin expression in membrane and HER2 expression were statistical significance (P0.05).Conclusions:The heightening expression and the expression position change of Ezrin play a regulating role on the occurrence,development and metastasis of breast cancer,which may be an important biological indicator in diagnosing the metastasis and prognosis of breast cancer.