Chronic myeloid leukemia (CML) [5] and chronic lymphocytic leukemia (CLL) [6], the most common hematological malignancies in the U.S.A and Europe [7], are characterized by a dependence on kinase pathways (see below) for leukemia cell growth and survival, and as a result have been very successfully treated with TK inhibitors. The gene discussed is TKT; the disease is B-cell chronic lymphocytic leukemia.