We investigated the immunohistochemical expression of the sonic hedgehog (SHH) signaling pathway-related proteins, PTCH, smoothened (SMO) and GLI-1, and of the SHH-induced bcl-2 oncoprotein in a series of primary OKC (pOKC), recurrent OKC (rOKC) and nevoid basal cell carcinoma syndrome-associated OKCs (NBCCS-OKCs), and compared them to solid ameloblastomas (SAMs), unicystic ameloblastomas (UAMs), 'orthokeratinized' OKCs (oOKCs), dentigerous cysts (DCs) and radicular cysts (RCs).