Plasma miR-21, miR-155, miR-10b, and Let-7a as the potential biomarkers for the monitoring of breast cancer patients

Abstract

There is a pressing need for further studies to categorize and validate circulating microRNAs (miRs) in breast cancer patients that can be one of the novel strategies for cancer screening and monitoring. The present study is aimed to investigate the expression of the circulating candidate microRNAs after the operation, chemotherapy, and radiotherapy in the non-metastatic breast cancer patients. Tumor tissue and plasma samples were collected from the 30 patients with recently diagnosed Luminal A breast cancer. Control plasma samples were collected from the 10 healthy subjects. A panel of four miRs including miR-21, miR-55, miR-10b, and Let-7a were selected and their expression levels were measured before and after the operation, chemotherapy, and radiotherapy by using Real-Time PCR technique. The plasma expression of the miR-21, miR-155, and miR-10b was significantly increased and the Let-7a plasma expression decreased in the breast cancer patients compromised to the control ones. There was a similar expression pattern of the miRs between the tissue and plasma samples. The plasma levels of the miR-21, miR-155, and miR-10b were significantly down-regulated and the Let-7a plasma level was up-regulated after the operation, chemotherapy, and radiotherapy compromised to the pre-treatment. There was a significant difference in the miR-155 plasma level after the operation, chemotherapy, and radiotherapy compromised with each other. Moreover, there was no significant difference between the plasma levels of the miRs after the radiotherapy compromised to the control cases. The operation, chemotherapy, and radiotherapy led to a more reduction in the oncomiRs and an increase in the tumor suppressor-miRs. It seems that monitoring miRs during treatment might be considered as a respectable diagnostic tool for monitoring of breast cancer patients.

Figure 1

Comparison of the selected plasma miRs between the breast cancer patients and control. The relative expression level of the miR-21 (A), miR-155 (B), miR-10b (C), and Let-7a (D) were normalized using SNORD RNA as reference RNA.

Figure 2

The differential expression of the selected miRs in both the tissue and plasma of the breast cancer patients. The relative expression level of the miR-21 (A), miR-155 (B), miR-10b (C), and Let-7a (D) were normalized using SNORD RNA as reference RNA. The line represents the median value.

Figure 3

Comparison of stage II/III feature of the patients with the plasma relative expression of the selected miRs. The relative expression level of the miR-21 (A), miR-155 (B), miR-10b (C), and Let-7a (D) were normalized using SNORD RNA as reference RNA.

Figure 4

The expression of the selected miRs in the breast cancer patients before and after the treatment. The relative expression level of the miR-21 (A), miR-155 (B), miR-10b (C), and Let-7a (D) were normalized using SNORD RNA as reference RNA. The line represents the median value. Post-OP: Post-Operation, Post-Chemo: Post-chemotherapy, Post-Radio: Post-Radiotherapy.

Figure 5

The expression of the selected miRs in the patients before and after the treatment compromised to the control. The relative expression of the miR-21 (A), miR-155 (B), miR-10b (C), and Let-7a (D) were normalized using SNORD RNA as reference RNA. The line represents the median value. Post-OP: Post-Operation, Post-Chemo: Post-chemotherapy, Post-Radio: Post-Radiotherapy.