Comparison of -catenin Expression in Keratocystic Odontogenic Tumor, Dentigerous Cyst and Ameloblastoma

Odontogenic keratocyst is now designated by the World Health Organization as a keratocystic odontogenic tumor (KCOT). According to recent reports Wnt pathway and ß-catenin are involved in the pathogenesis of the majority of odontogenic and neoplastic lesions. The aim of this study was to evaluate the expression of ß-catenin in KCOT and compare it with those of dentigerous cyst and ameloblastoma. Expression of ß-catenin was investigated by immunohistochemistry using specific monoclonal antibodies in 57 formalin-fixed paraffin-embedded samples of KCOT, dentigerous cyst and ameloblastoma (19 samples in each group). The expression of catenin protein was observed separately in the membrane, cytoplasm and nucleus of epithelial cells. Percentages of expression of membranous, cytoplasmic, and nuclear ß-catenin were 68.4%, 89.5% and 5.3% for KCOT; 78.9%, 100%, and 26.3% for ameloblastoma and 42.1%, 84.2%, and 5.3% for dentigerous cyst, respectively. The expression of membranous ß-catenin in the dentigerous cyst was significantly lower than that in KCOT and ameloblastoma (P<0.05). In other cases, there were no significant statistical differences between the three groups. Membranous expression of ß-catenin might be useful in differentiation of KCOT and ameloblastoma from dentigerous cyst. However, intracellular accumulation of this protein cannot be used to prove the neoplastic nature of KCOT versus dentigerous cyst. Moreover, considering the intracellular accumulation of ß-catenin in most cases in all the three lesions, it seems that ß-catenin changes might play a role in development of odontogenic epithelium in this lesion through deregulation of cell cycle. KEYWORDS