Cell lines used in this study include standard human T cell leukemia (Jurkat), human B cell leukemia (NALM6) cell lines, and a patient-derived B cell leukemia cell line that we have previously reported [658w, (21)]. All cell lines were cultured in RPMI 1640 medium (catalog no. R0883; Sigma-Aldrich) supplemented with 10% fetal bovine serum (Sigma-Aldrich), 0.5% l-glutamine (BioConcept), and 0.5% penicillin/streptomycin (Life Technologies) and incubated at 37° until colonies reached a population size of about 5 × 105 cells/ml. Cells were passaged every 3 days by dilution of the cells to a concentration of around 1 × 105 cells/ml.