ABT-199 has achieved promising anti-leukemia activity in patients with chronic lymphocytic leukemia (CLL) (Molica, 2015), and it has been reported to have preclinical activities in estrogen-receptor-positive breast cancer, acute myeloid leukemia (AML), early T cell progenitor leukemia, Myc-driven B cell lymphomas, and acute lymphoblastic leukemia (Alford et al., 2015, Chonghaile et al., 2014, Pan et al., 2014, Souers et al., 2013, Vaillant et al., 2013, Vandenberg and Cory, 2013). This evidence concerns the gene ESR1 and acute myeloid leukemia.