ENU-treated mice with Apc haploinsufficiency develop a fatal macrocytic anemia at an accelerated pace, regardless of Egr1 or Tp53 expression. (A) Kaplan-Meier survival curve of Apc^del/+mice, or mice crossed with Egr1^+/−; Tp53^+/−; or Egr1^+/− and Tp53^+/−. Mice were treated with 3 doses of pI-pC at 2 months of age, and ENU, where indicated, at 3 months. All mice treated with ENU died at a significantly faster rate (P < .0001). (B) CBC are shown for ENU-treated Apc^fl/+and Apc^del/+mice or Apc^del/+mice crossed with Egr1^+/−(E), Tp53^+/− (P), or Egr1^+/−, Tp53^+/− (EP). CBCs of Apc^del/+ mice were taken at the time of sacrifice, when the mice were severely anemic and moribund. Blood counts of ENU-treated Apc^fl/+ control mice were taken during a similar timeframe, but mice were not moribund. MO, monocytes; PLT, platelets; WBC, white blood cells.