Replacement of the Atm^-/- hematopoietic compartment by BMT prevents lymphoma.Atm^-/- mice were conditioned with cyclophosphamide and anti-CD4 and -CD8 monoclonal antibodies. Mice that received C3H bone marrow (▴) had a significantly longer lifespans than Atm^-/- control mice that did not receive C3H bone marrow (▪). Shown are the combined results of 5 experiments.