H2AX and breast cancer: In HR pathway, other miRNAs play an important role in DSB repair: miR-138 targeting H2A.X in osteosarcoma cells, miR-146a and miR-146b-5p targeting BRCA1 in breast cancer, miR-1 targeting BRCA1 in prostate tumor cell lines, and miR-1245 targeting BRCA2 in breast cancer cell lines (23).