To determine the potential role of TWIST-1 in leukemia, we quantified the mRNA and protein expression of TWIST-1 in the myeloid cell lines NB4, KG1a, J6–1, U937, HL-60, and K562, originally derived from patients with myeloid leukemia, as well as CEM, Ramos, Jurkat, and Namalwa derived from leukemia of lymphoid origin, or lymphoma patients. The gene discussed is TWIST1; the disease is myeloid leukemia.