Abstract: Objective To investigate the relationships between the expression of HER3,HER2,ER and PR,and their effects on the clinical prognosis of human breast carcinoma. Methods The expressions of HER3,HER2,ER and PR were studied in 136 cases with breast carcinoma by using SP immunohistochemistry.The endpoint was overall survival(OS). Results HER2,HER3,ER and PR expression was detected in 136 cases with positive rates of 50%,41.18%,60.9% and 27.21%,respectively.The expression intensity of HER3 in breast carcinoma had no significant correlation with the age,lymph node metastasis,pathological types,TNM stage,chemotherapy of the patients(P>0.05).Compared with those patients with HER3-negitive profiles,the patients with HER3-positive profiles had significantly lower OS(P=0.015).The patients with HER3(+)HER2(+) expression profiles had significantly lower OS(P=0.047) than other groups.There is no interaction between HER3 and PR expression(P=0.214)，but HER3 have a inverse relationship with ER expression(P=0.001).Overexpression of HER2 and HER3 was highly correlated(P=0.000). Conclusion HER3 expression is an independent predictor of breast cancer.Patients with HER3-negative have a longer OS. Key words：