DETECTION OF APOPTOSIS-RELATED FACTORS AND APOPTOTIC CELLS IN AMELOBLASTOMAS - ANALYSIS BY IMMUNOHISTOCHEMISTRY AND AN IN-SITU DNA NICK END-LABELING METHOD

To clarify the possible role of apoptosis in odontogenic epithelium, a poptosis-related factors and apoptotic cells were examined by immunohi stochemistry and an in situ DNA nick end-labelling method. Expression of bcl-2 protein was detected in both normal and neoplastic odontogeni c epithelium, whereas expression of p53 protein was detected only in n eoplastic but not in normal odontogenic epithelium. The prevalence of cases positive for Lewis(y) antigen in ameloblastomas was significantl y lower than in enamel organs. Correlation between these factors and a poptotic cells presented by an in situ DNA nick end-labelling method w as not clear. The number of apoptotic cells in ameloblastomas was sign ificantly greater than in normal odontogenic epithelium, and apoptotic reactions in the granular cell type ameloblastoma tended to be more f requently detected than in other types of ameloblastomas. These result s suggested that apoptotic cell death might play an important role in oncogenesis and/or tissue differentiation in odontogenic epithelium.