Abstract: Objective: To detect the expression levels of microRNA200 (miR200) family in the plasma of the breast cancer patients and the normal controls, and to evaluate their potential values in the screening, progression and prognosis evaluation of breast cancer.Methods: A total of 82 cases of plasma samples of the patients with breast cancer (breast cancer group) and 30 cases of healthy plasma samples (control group) were collected.The microRNAs(miRNAs) were extracted from the plasma samples, the expression levels of miR200 family (miR200a, miR200b, miR200c, miR141 and miR429) were quantified by using real-time PCR technique.The receiver-operating characteristic (ROC) curve was used to assess the diagnostic value of miRNAs, and the associations between the levels of miRNAs and the clinicopathological characteristics were analyzed.Cox proportional hazard mode was used for survival analysis.Results: Compared with control group, the expression level of miR141 in the plasma of the patients in breast cancer group was decreased(P<0.01),and the area under the ROC curve (AUC) was 0.717(P<0.01); the expression level of miR200b was also decreased (P=0.006), the AUC was 0.685 (P= 0.003); the expression levels of miR200a, miR200c and miR429 had no significant differences between two groups(P=0.268, P=0.075, P=0.872). The AUC of combination of miR200b and miR141 was 0.735(P<0.01), the efficacy was superior to that of miR141 used alone. There were no statistically significant associations between the expression levels of miR200 family and the clinicopathological characteristics of breast cancer and postoperative overall survival(P>0.05).Conclusion: MiR200b and miR141 are likely to become the molecular biological parameters for the diagnosis of breast cancer.

Key words: breast neoplasms, microRNA, miR200, miR200a, miR200b, miR200c, miR141, miR429