Isolation and Culture of Myeloid and Lymphoid Leukemia Cells

All clinical samples were obtained with informed consent with approval by the Institutional Review Boards of Stanford University, Oregon Health & Science University, the Children’s Oncology Group, and Erasmus Medical Center/Sophia Children’s Hospital. Blood or bone marrow from patients was separated on a Ficoll gradient and mononuclear cells were treated with ACK lysis buffer. The only exceptions to this procedure were cases of atypical CML or chronic neutrophilic leukemia, where samples were only processed with ACK lysis buffer to preserve the neoplastic granulocytes that would otherwise be lost on the Ficoll gradient. Cells from myeloid leukemia samples were cultured in R10 (RPMI-1640 medium supplemented with 10% FBS (Atlanta Biologicals, Lawrenceville, GA), L-glutamine, penicillin/streptomycin (Invitrogen, Carlsbad, CA), and fungizone (Invitrogen)) supplemented with 10⁻⁴ M 2-mercaptoethanol (Sigma). Cells from lymphoid leukemia samples were cultured in R20 (RPMI-1640 medium supplemented with 20% FBS (Atlanta Biologicals, Lawrenceville, GA), L-glutamine, penicillin/streptomycin (Invitrogen, Carlsbad, CA), and fungizone (Invitrogen)) supplemented with 10⁻⁴ M 2-mercaptoethanol (Sigma) insulin-transferrin-sodium selenite (Invitrogen).