Fig. 1. Myc-induced lymphomagenesis is inhibited by Mdm2 haplo-insufficiency. Kaplan–Meier survival curves of Mdm2^+/–Eµ-myc transgenic, Mdm2^+/+Eµ-myc transgenic, p53^+/–Eµ-myc transgenic and p53^+/–Mdm2^+/–Eµ-myc transgenic mice. The average survivals are 44.3, 20.6, 5.6 and 5 weeks, respectively (log-rank test, P < 0.001). n, the number of mice in each group. Vertical lines indicate ages of surviving mice. Three (3/58) Mdm2^+/+Eµ-myc transgenic mice and nine (9/45) Mdm2^+/–Eµ-myc transgenic mice are still alive, whereas none of the p53^+/–Eµ-myc and p53^+/–Mdm2^+/–Eµ-myc transgenics is alive. The Kaplan–Meier curves are right-censored because the study was terminated before all of the animals were sacrificed. Therefore, although 20% (9/45) of the Mdm2^+/–Eµ-myc transgenic mice are still alive at 70 weeks, the Kaplan–Meier estimate at 70 weeks is lower because there were fewer animals at risk of death at 70 weeks. Lymphoma was documented in all of the animals.