DIFFERENTIATION OF ODONTOGENIC KERATOCYSTS FROM OTHER ODONTOGENIC CYSTS BY THE EXPRESSION OF BCL-2 IMMUNOREACTIVITY

Odontogenic keratocysts (OKC) present an aggressive course with a mark ed tendency to recurrence. The epithelium of OKC is thought to have an intrinsic growth potential and has been shown to present a higher rat e of proliferation as compared to other types of cyst. bcl-2 has a rol e in the extension of cell survival. The objective of the present stud y was to evaluate the bcl-2 protein expression in different odontogeni c cysts. A total of 19 dentigerous cysts (DC), 20 radicular cysts (RC) and 14 OKC were used in the present study. DC and RC showed an almost complete negativity for bcl-2. OKC, on the other hand, presented in a ll cases a strong positivity in the cells of the basal layer, with, in most cases, more than 50% of the cells positive. This bcl-2 positivit y of the basal layer of OKC could point to an abnormal control of the cell cycle. The bcl-2 protein overexpression could then produce an inc rease in the survival of the epithelial cells, and this increased life span could, in turn, lead to the peculiar aggressive growth pattern of OKC. Moreover the bcl-2 staining can be useful to differentiate OKC f rom other types of odontogenic cysts. (C) 1998 Elsevier Science Ltd. A ll rights reserved.