Both the Hh/Smo pathway and the Wnt/Fz pathway have been shown to be required for the onset and maintenance of chronic myelogenous leukemia (CML) [16], [17] suggesting that β-arrestins may play a role in the pathogenesis of hematopoietic malignancies. Here, SMO is linked to chronic myelogenous leukemia, BCR-ABL1 positive.