Abstract: Objective To investigate the expression of cyclooxygenase-2（COX-2） and Survivin in ameloblastoma (AB) tissues. Methods A total of 60 AB samples (primary AB 40 cases, recurrent AB 20 cases) and 60 normal oral mucosas were collected from the Affiliated Hospital of Chengde Medical College. The AB samples included 12 acanthomatous types, 18 follicular patterns, 18 plexiform patterns, 6 basal cell ameloblastomas and 6 desmoplastic ameloblastomas. The expression levels of COX-2 and Survivin were detected by immunohistochemistry and Western blot methods in AB and normal oral mucosa. The expressions of COX-2 and Survivin were compared between different types and tissues of AB. Results The positive rate of COX-2 was significantly higher in AB (82.7%) than that in normal oral mucosa (10.0%). The positive rate of Survivin was significantly higher in AB (83.3%) than that in normal oral mucosa tissues (16.7%). The expression of COX-2
(0.781±0.142) was higher in AB than that of normal oral mucosa tissues (0.179±0.056). The expression of Survivin (0.447± 0.139) was significantly higher in AB than those in normal oral mucosa tissues (0.072±0.017). There was a positive correlation between the expression of COX-2 and Survivin (r=0.778， P＜0.05). There were no significant differences in the positive expressions of COX-2 and Survivin between different types of AB (P>0.05). Conclusion COX-2 and Survivin were overexpressed in AB, which may be involved in the occurrence and development of AB.

Key words: ameloblastoma, cyclooxygenase-2, survivin, immunohistochemistry, blotting, Western