Resumen de Juvenile trabecular ossifying fibroma: immunohistochemical expression of MDM2, CDK4 and p53 compared to conventional ossifying fibroma
Nikolaos G. Nikitakis, Maria Georgaki, Stavroula Merkourea, Risa Chaisuparat, Gary Warburton, Márcio Ajudarte Lopes, J.C. Papadimitriou, Robert A. Ord
Background: Juvenile ossifying fibroma (JOF) is an uncommon benign fibro-osseous lesion of the craniofacial skele- ton; compared to conventional ossifying fibroma (OF), JOF is characterized by local aggressiveness and propensity for recurrence. The biologic basis for this different biologic behavior between JOF and OF remains elusive. The aim of this study was to evaluate the immunohistochemical expression of MDM2, CDK4 and p53, molecules associated with bone oncogenesis, in the trabecular variant of JOF.
Material and Methods: The study material consisted of five cases of trabecular JOF, affecting three male and two fe- male patients with a mean age of 11.8 years. Three cases arose in the maxilla and two in the mandible. All cases were initially treated by enucleation; two cases recurred necessitating more aggressive treatment. Immunohistochemical study of MDM2, CDK4 and p53 was performed in all cases, as well as in five control cases of conventional OF.
Results: CDK4 positivity was noted in all JOF cases; the staining pattern was diffuse and strong in 4 cases and focal and weak in one case. In contrast, 4 out of 5 cases of OF were weakly and focally CDK4 positive, the remaining one being negative. Immunostaining for MDM2 was observed in 3 JOF cases; all OF were MDM2 negative. All cases of OF and JOF were negative for p53, except for one focally positive JOF case.
Conclusions: CDK4 and MDM2 expression in the trabecular variant of JOF is higher compared to conventional OF.
In contrast, p53 expression is almost universally negative in JOF and OF. Despite some overlapping features, diffe- rential expression patterns of proteins involved in bone oncogenesis can elucidate the pathogenesis and may facilitate accurate diagnosis and prediction of behavior of bone tumors in the craniofacial region.
