Abstract: Objective 　To evaluate the feasibility of detecting EGFR mRNA by RT-PCR in peripheral blood of patients with breast cancer, to explore the relationship between EGFR mRNA in peripheral blood and EGFR protein in corresponding tumor tissues and to explore its clinical significance. Methods 　RTPCR assay was applied to detect the expression of EGFR mRNA in the peripheral blood of 40 patients with breast cancer, 25 patient s with benign breast diseases and 30 healthy donors. Expression of EGFR protein in corresponding tumor tissues was detected by immunohistochemistry. Results 　EGFR mRNA was expressed in 13 of 40 (32. 5 %) patients with breast cancer, compared with both healthy donors (0 %) and benign breast disease patient s (0 %) ( P < 0. 01) . On the other hand, expression of EGFR protein in corresponding tumor tissues was detected in 25 (62. 5 %) of 40 breast cancer patient s by immunohistochemistry. Patients with high expression grade of EGFR protein displayed high expression rate of EGFR mRNA in peripheral blood as well. The expression of EGFR gene was significantly correlated with clinical stage, histological grading and ER, but had no coincidence with pathologic type, tumor size, lymph node metastasis, PR and HER-2. Conclusion 　Detection of EGFR mRNA in peripheral blood by RT-PCR may be an effective method of detecting CTCs in breast cancers. It may be used as a prognostic indicator and may also cont ribute significantly to early diagnosis of micrometastasis, the decision on therapies and evaluation of treatment effect .