So even after irradiation induced DNA breaks are repaired (probably corresponding to the non-irradiation conditions, which means the situation that external irradiation induced DNA breaks are fully repaired corresponds to the situation that no irradiation or irradiation induced DNA damage are encountered), the ATM switch can not be shut down and preserves highly activated state to ensure undamped pulses of p53 in the tumor cells. The gene discussed is TP53; the disease is neoplasm.