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. The gene discussed is ATM; the disease is neoplasm.