The expression of Pim-1, Pim-2, and Pim-3 proteins in A-MuLV–transformed pre-B-cell lines derived from fetal liver and bone marrow. v-Abl–transformed cells were treated in a time course with imatinib, an Abl kinase inhibitor. A Western blot of cell lysates was probed with indicated antibodies. Lysate of Pim-1^−/−/Pim-2^−/− cells was used as a control.