SMO and hepatocellular carcinoma: HH signaling is maintained at low activity in normal mature hepatocytes but re-activated in the liver of patients with HCC, as illustrated by elevated levels of SHH, SMO, GLI2, and HH target genes in HCC tissues compared to the adjacent normal tissues (Huang et al., 2006; Sicklick et al., 2006; Crompton et al., 2007; Pereira Tde et al., 2010).