Objective To explore the quantitative expression of estrogen receptor(ER),progesterone receptor(PR)in breast hyperplasia and its Clinical significance.Methods The expression of ER and PR was examined by immunohistochemical S-P method and quantitative analysis technique in 20 cases a piece of epithelial hyperplasia of usual type,atypical hyperplasia(mild,moderate,severe)and intraductal carcinoma,which contrasted with 20 cases of usual breast.Results The difference of the expression of ER and PR between usual breast or epithelial hyperplasia of usual type and atypical hyperplasia or intraductal carcinoma was significant(P50%,there was significant difference between moderate dysplasia and mild dysplasia,but no significant difference between moderate dysplasia and severe dysplasia,intraductal carcinoma.Conclusions The abnormal expression of ER and PR may be an early event in the progression of breast carcinoma,it could be used for early diagnosis of breast premalignancy and as a effective mark to monitor the prognosis.