Fancc^−/−;Fancg^−/− mice have a shortened life span and an increased risk of BMF despite similar MMC sensitivity of Fancc^−/−, Fancg^−/− and Fancc^−/−;Fancg^−/− cells. (A) Sensitivity of WT, Fancc^−/−, Fancg^−/−, and Fancc^−/−;Fancg^−/− cells to MMC. Data represent mean ± SEM of 3 independent experiments each of which was plated in triplicate cultures isolated from the bone marrow of 3-month-old syngeneic mice. WT is significantly different from any of the other experimental groups, which had comparable sensitivity, *P < .001 by 2-way ANOVA. (B) Kaplan-Meier curve shows a significant decrease in survival of Fancc^−/−;Fancg^−/− mice compared with WT, Fancc^−/− or Fancg^−/− mice, n = 8/genotype. *P = 0.0004 for Fancc^−/−;Fancg^−/− compared with WT, Fancc^−/− or Fancg^−/− by the log-rank test for trend. (C) Fancc^−/−;Fancg^−/− mice, but not WT, Fancc^−/− or Fancg^−/− mice, develop aplastic anemia and myeloid malignancies. Subpanels iv and ix are from a 20-month-old Fancc^−/−;Fancg^−/− mouse and subpanels v and x are from a 23-month-old Fancc^−/−;Fancg^−/− mouse.