Abstract: Objective:To investigate the clinical significance of the detection of circulating tumor cells(CTCs) in peripheral venous blood of breast cancer patients.Methods:The CTCs in peripheral venous blood of 60 patients with breast cancer before new stage treatment were examined using density gradient centrifugation combined with flow cytometry(FCM),and the expression levels of estrogen receptor(ER),progesterone receptor(PR),human epidermal growth factor receptor-2(HER-2),p53 and Ki-67 were detected using the immunohistochemical method.Twenty healthy female volunteers were set as the control group at the same time.Results:The positive rate of CTCs in observation group was 38.3%(23/60),the positive CTCs was not detected in control group,and the difference of the positive expression of CTCs between two groups was statistically significant(P<0.01).The differences of the positive expression of CTCs in different ages and pathological types patients were not statistically significant(P>0.05).The difference of the positive expression of CTCs in different TNM stages patients was statistically significant(P<0.01).The positive expression of CTCs in metastatic breast cancer patients was significantly higher than that in nonmetastatic breast cancer patients(P<0.01).The differences of the positive expression of CTCs in patients with different ER,PR,HER-2,Ki-67 and molecular classification were not statistically significant(P>0.05).Conclusions:The CTCs is related to the TNM staging and metastatsis of breast cancer,which has a great significance in the diagnosis,treatment and evaluating prognosis of breast cancer.