ATM and cancer: MiR-34a sensitizes tumors to IR by targeting RAD51, a central regulator of DNA repair.14 The N-Myc-regulated miR-421 targets the 3′-untranslated region (3′UTR) of ATM mRNA and increases radiosensitivity.15 Elevation of miR-185 sensitizes cancer cells to radiation by targeting ATM and ATR.16 It was previously shown that miR-182 targets BRCA1 to impact homologous recombination-mediated DNA repair and increase cellular radiosensitivity.17 Currently, there is an increasing interest in defining functional miRNAs involving in the tumor radiation response to increase radiosensitivity.