Objective To investigate the expressions of PTEN and Caspase-3 proteins in human breast carcinoma,and to evaluate their clinicopathological implications during the tumorigenesis and progression of breast cancer.Methods The expressions of PTEN and Caspase-3 proteins in 95 cases of breast cancer and 15 cases of benign breast diseases were investigated immunohistochemically.Correlations between the expression of PTEN protein,Caspase-3 protein,and clinicopathological features of breast cancers were analyzed.Results The loss expression rate of PTEN protein in tumor tissues was significantly higher than that in benign breast diseases(33.7% vs.0,P<0.01).Analysis of the clinicopathological features showed that PTEN expression level was negatively correlated with TNM stage,histological grade,axillary lymph node status,recurrence,and metastasis(P<0.05).The positive expression level of Caspase-3 was negatively correlated with TNM stage(P<0.01),but not related with histological grade,axillary lymph node status,recurrence,or metastasis(P>0.05).In addition,the expression of PTEN protein had significantly positive correlation with the expression of Caspase-3 protein in breast cancer(P<0.01).Conclusion The combination detection of PTEN and Caspase-3 may serve as an important index to estimate the pathobiological behavior and prognosis of breast cancer.