Constitutive activation of Stat5 has also been linked to a variety of blood-derived malignancies such as BCR-ABL-induced chronic myeloid leukemia (CML [8]), acute myeloid leukemia (AML) and acute lymphoid leukemia (ALL [9]). The gene discussed is STAT5A; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.