Loss of Bim but not Bad or Bmf protects Eμ-myc lymphomas from drug-induced apoptosis in vitro. Freshly isolated Eμ-myc lymphoma cells were cultured on supporting irradiated NIH-3T3 cells in the presence of chemotherapeutic agents at the indicated concentrations for 24 hours. Cell death was determined by annexinV/7-AAD staining in CD19⁺ tumor cells. Specific cell death relative to cells cultured without the addition of any drugs was calculated. Values represent means ± SD of 4 or more animals/genotype. *P < .05, **P < .01, ***P < .001, ****P < .001.