Fig. 1. Site of action and inhibit of different HPI on the hedgehog pathway. PTCH: patched: SMO: smoothened protein: SUFU: suppressor of the fused protein: GSK3B: glycogen synthetase kinase 3B; PKA: protein kinase A; GLI: transcription factor GLI; PDE: cyclin nucleotide phosphodiesterases; PI3K/Akt: phosphoinositide 3 kinase; HPI: hedgehog pathway inhibitors.