Immunohistochemical comparison of the expression of p53 and MDM2 proteins in ameloblastomas and keratocystic odontogenic tumors

Ameloblastoma and keratocystic odontogenic tumor (KOT) is characterized by a benign but locally invasive behavior with a high risk of recurrence. MDM2 (murine double minute 2), an amplifier of cell proliferation, and p53, a tumor suppressor gene, are overexpressed in some odontogenic lesions. The aim of this study was to compare the expression of MDM2 and p53 in ameloblastoma and KOT as 2 lesions with similar biologic behavior, by immunohistochemistry. The expressions of MDM2 and p53 proteins were determined in 39 ameloblastomas (15 follicular types, 15 plexiform types, and 9 unicystic types) and 15 KOTs. P53 protein was expressed in 100% of KOTs and 77.8% of ameloblastomas, and MDM2 was detected in 74.8% of ameloblastomas and 80% of KOTs. There was no statistical difference between MDM2 and p53 expressions in different subtypes of ameloblastomas and also when KOTs were compared with them (P > 0.05). There was a significant difference between immunohistochemical reactivity of MDM2 among subtypes of ameloblastomas (P < 0.05). MDM2 and p53 expressions were positively correlated. Overexpression of p53 and MDM2 is associated with the pathogenesis and oncogenesis of ameloblastomas and KOT. Overexpression of these markers can contribute to similar biologic behavior of these lesions.