Kaplan-Meier analysis of overall survival in Puma^+/+, Puma^+/−, Puma^−/−, and p53^−/− mice challenged with 10 Gy of γ-irradiation. The plots of short-term analysis (42 days, top) and long-term analysis (more than 600 days, bottom) were shown, respectively. All the Puma^+/+ (n = 23, red) and p53^−/− (n = 21, green) mice died within 35 days and there was no significant difference between these 2 groups (P = .07). The Puma^−/− (n = 24, blue) and Puma^+/− (n = 32, purple) mice survived much longer. There are significant differences when Puma^−/− or Puma^+/− groups were compared with Puma^+/+ or p53^−/− groups (P < .01in all groups).