Ito et al. (2008) demonstrated an important role of the promyelocytic leukemia protein (PML) tumor suppressor in the maintenance of quiescent CML stem cells, introducing the possibility of eradicating CML stem cells with arsenic trioxide (As2O3) [234], an ROS generator that inhibits PML. The gene discussed is PML; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.