PTCH1 and olfactory neuroblastoma: Olfactory neuroblastoma (ONB), another rare tumor of the epithelium in the nasal cavity, also showed activation of the Hedgehog pathway (IHC staining of PTCH1, GLI1, and GLI2), as well as inhibition by Hedgehog pathway inhibitor cyclopamine in vitro on two ONB cell lines [34].