By immunohistochemical staining of Sirt3, p-ATM, p-Chk2 and γ-H2AX in each group of tumor tissues, it was also found that the activation of γ-H2AX was more pronounced in Sirt3 knockdown group, and the radiation-induced activation of p-ATM was significantly attenuated. The gene discussed is ATM; the disease is neoplasm.