Hh signaling is activated in Bcr-Abl-positive leukemia stem cells (LSC), and pharmacological inhibitors of Smo reduced leukemia stem cells in vivo [16], suggesting that Smo inhibition could be an effective treatment strategy in reducing tumor relapse and drug resistance in chronic myeloid leukemia. The gene discussed is SMO; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.