SMO and ameloblastoma: In the carcinogenesis, the accumulation of driver gene mutations was regarded as a main factor in various carcinomas.6, 20, 21 In the ameloblastoma, SMO and BRAF mutations were frequently seen.22 Interestingly, BRAF mutation was also reported in AC.23 Nobusawa et al reported a case of AC which developed in preexisting AB with a mutation of p53 gene.24 Thus, it is suggested that some driver gene mutations accumulated in AB contribute to AC carcinogenesis.