SMO and cancer: Aberrant Hh signaling, which can be achieved by mutational inactivation of Ptch, aberrant expression of its ligand, constitutive activation of SMO or gene amplification of GLI-associated transcription factors, has been implicated in the initiation and/or maintenance of different cancer types, including basal cell carcinoma (BCC), gastrointestinal, lung, and brain tumors and rhabdomyosarcoma [3].