Effect of Photodynamic Therapy on the microRNA Level in Breast Cancer Tissues of Female Wistar Rats

The expression of microRNA (miR-21, miR-221, miR-27a, and miR-429) was studied normal and tumor breast tissues of female Wistar rats before and after photodynamic therapy. In breast cancer, the levels of oncogenic microRNA (miR-21, miR-221, and miR-27a) were increased, while the level of tumor-suppressing miR-429 was reduced in comparison with the intact group. After photodynamic therapy, suppression of the expression levels of oncogenic microRNAs (miR-21, miR-221, and miR-27a) was noted. The level of tumor-suppressing miR-429 in breast tumor tissues remained reduced, as in the untreated breast cancer group.