Dr. Tomasson has made important contributions to our understanding of leukemia biology. He has demonstrated that tyrosine kinase (TK) oncogenes mediate disease progression in an animal model of AML1/ETO-induced AML, and that dysregulation of c-Myc expression may be a critical downstream mediator of myeloid leukemogenesis. By improving our understanding of the role that tyrosine kinase oncogenes play in the development of myeloproferative diseases and acute myeloid leukemia (AML), he has provided an important foundation for the development of improved targeted therapies in these diseases.