PTCH1 and Keratocystic odontogenic tumor: Barreto et al. identified PTCH1 mutations in odontogenic keratocysts—designated keratocystic odontogenic tumours (KCOTs) in the 2005 WHO classification but reverted to the cystic term OKC in the 2017 revision—including both lesions that arise in patients with nevoid basal cell carcinoma syndrome and truly sporadic cases; many of the variants are predicted to truncate the PTCH1 protein.23 These mutations likely disrupt normal Hedgehog signaling.