CD38 and precursor B-cell acute lymphoblastic leukemia: CD38 is expressed in several hematological malignancies, including acute B lymphoblastic leukemia (B-ALL) (85), acute myeloid leukemia (AML) (85–87), mantle cell lymphoma (MCL) (88), chronic lymphocytic leukemia (CLL) (89, 90), multiple myeloma (MM) (91) and NK/T cell leukemia (T-ALL) (92, 93) (Figure 2).