Radiotherapy induced microRNA expression in the plasma of breast cancer patients

Objective: To investigate the expressions of miR-210-3p, miR-221-3p, miR-21-5p and miR-150-5p in the plasma of breast cancer patients before and after radiotherapy in order to establish reliable early biomarkers of non-uniform radiation injuries. Methods: Blood samples were collected from 13 patients before radiotherapy (0 Gy) and 24 h after radiotherapy of 2, 10, 20, 30 Gy. The miRNAs in the blood plasma were detected with qRT-PCR. Results: The levels of miR-210-3p, miR-221-3p, miR-21-5p had no significant difference among different dosage groups after radiotherapy(P > 0.05). There was no significant difference between the expression of miR-150-5p before and after 2 Gy radiotherapy(P > 0.05). While the relative level of miR-150-5p gradually decreased to 0.808, 0.605, 0.565 (χ² = 18.76, P < 0.05) with increased accumulative dosage of 10, 20, and 30 Gy, respectively. In addition, the miR-150-5p expression levels had no relationship(P > 0.05) with situations (positive or negative group) of human epidermal growth factor receptor 2 (HER2), estrogen receptor (ER) and progesterone receptor (PR) in the breast cancer cells. Conclusions: Ionizing radiation could reduce the expression of miR-150 in the plasma of breast cancer patients in a dose-dependent manner. (authors)