AMELOBLASTOMAS vs ODONTOGENIC CYSTS: ROLES OF COX-2, VEGF IN ANGIOGENESIS

Objective: To evaluate the expression of COX-2 and VEGF in ameloblastomas, keratocysts, dentigerous cysts and periapical cysts and their correlation to angiogenesis. Methods: We studied: 28 ameloblastomas, 19 keratocysts, 17 dentigerous cysts and 21 periapical cysts. The specimens were processed using routine histologic techniques and immunohistochemistry for COX-2, VEGF and CD 34. The expression of COX-2 and VEGF was assessed by its intensity as negative (0), mild (1), moderate (2) and intense (3). The measurement of microvessel density (MVD) was made by the Chalkley method through CD34, using a minimum of five (5) hot spots. Results: The COX-2 expression was different among the lesions (p = 0.0083), being more intense in ameloblastomas. The lesions did not differ in relation to VEGF. The number of vessels was similar between ameloblastomas and periapical cysts, and significantly greater (p = 0.0001) than in dentigerous cysts and keratocysts. Conclusions: The expression of COX-2 varied between types of odontogenic lesions. It was more intense in ameloblastomas than in non-neoplastic cysts, suggesting that this may have a role in tumorigenesis. Ameloblastomas and periapical cysts showed higher vascular proliferation, as compared to dentigerous cysts and keratocysts. This reflects the neoplastic nature of ameloblastomas as well as the inflammatory reaction surrounding periapical cysts. The absence of correlation between COX-2 expression and CD34 shows that they are independent features, and suggests that other precursors of angiogenesis may exist in the development of odontogenic tumors and cysts.