Abstract: Objective: To explore the expression and significance of nerve growth factor(NGF) and its receptor(p75) in breast cancer.Methods: The expressions of NGF and p75 in cancer tissuo of 118 patients with breast disease were detected using immunohistochemical method of PV-9000.Results: The NGF expression in mammary tumor epithelial cells was detected,the positive expression rate of NGF in malignant tumor was higher than that in benign tumor(P< 0.05),the difference of the NGF expression in situ and invasive carcinoma was not statistically significant(P >0.05).The p75 expression in the mammary gland myo-epithelial cells was detected,the positive expression rate of p75 in benign tumor was higher than that in malignant tumor(P< 0.05).The differences of the positive expression rate of NGF in tumor grade and lymph node metastasis,and patient age were not statistically significant(P >0.05).The difference of the positive expression rate of p75 in patient age was not statistically significant(P >0.05),but in tumor grade and lymph node metastasis,the differences were statistically significant(P< 0.01 and P< 0.05).Conclusions: NGF may be a molecular event of the occurrence and development of breast cancer,but it is unrelated with the invasion of breast cancer.p75 can be used as a molecular marker of malignant degree of breast cancer.