As demonstrated in Figure 5D, concomitant inactivation of Myh4 and Trp53 or Atm and Trp53 led to faster mammary tumor development than inactivation of Trp53 alone, shown as median overall survival times of 299 days for the Myh4 group, 273 days for the Atm group, and 490 days for the NT control group. The gene discussed is TP53; the disease is breast cancer.