KRT5 and neoplasm: Histological examination of these tumours revealed characteristics of ameloblastic odontomas (or odontoameloblastomas) that agreed with the international classification of dental tumours in mice.17 The ameloblastic odontomas of both p53EKO/K5-IKKβ and Ink4a/ArfKO/K5-IKKβ mice appeared as well-circumscribed tumours that showed differentiation into hard dental tissues, normally located in the central areas of the tumour, and soft tissues composed of proliferating ameloblastic epithelium, generally located at the periphery of the tumour (Fig. 2g–j).