Taken together, these results indicate that whereas apoE3-expressing bone marrow cells limit atherosclerosis progression, and atherosclerotic lesions in ApoE−/− mice with ApoE−/− and APOE2 bone marrow cells were early-stage lesions after 8 weeks of Western diet feeding, the lesions in APOE4 bone marrow–recipient mice have advanced to a more complex stage with cell necrosis. The gene discussed is APOE; the disease is atherosclerosis.