PTCH1 and Keratocystic odontogenic tumor: One of the most debated topics in the 2017 classification was the decision to transfer keratocystic odontogenic tumor back into the cyst category as odontogenic keratocyst (OKC), with the evidence put forward for reclassification based on aggressive growth, high recurrence after treatment, and most importantly, mutations in the PTCH gene [19].