APEX1 and breast cancer: Studies have reported that downregulation of miR-520h contributes to anticancer activity in human breast cancer and human cervical cancer cell lines [28]; miR-520h promotes drug resistance to paclitaxel by targeting OTUD3-PTEN axis in breast cancer [29]; miR-520h overcomes bortezomib resistance in multiple myeloma via suppressing APE1 [30].