ABSTRACT
P53 has been known as a tumor suppressor gene and also Ki-67 is a cell cycle regulator. The aim of present study was to investigate P53 and Ki-67 protein expression in the epithelial lining of odontogenic cysts and its correlation with their biologic behavior and the degree of inflammation within the cyst wall. P53 and Ki-67 immunoreactivity in 58 odontogenic cystic lesions including 19 Keratocysts, 20 dentigerous cysts and 19 radicular cysts were studied, using a biotin-streptavidin peroxidase method. Frequency of P53[+] Lesions in three groups was not statistically significant and there was no correlation between intensity of staining for P53 and Ki-67 proteins. But we found positive relationship between inflammation and intensity of P53 staining in odontogenic keratocyst. Ki-67 expression in odontogenic keratocyst was higher than dentigerous cyst and radicular cyst, but in this study we could not find any correlation between Ki-67 expression and degree of inflammation.Since we couldn't show any Discrepancies in distribution of P53, so the existence of greater proliferative potential and recurring of the odontogenic keratocyst may not be due to higher immortality and continual persistant, compared to other types of examined cysts, but it may be associated with increased potential of cell division. Mean while, expression of Ki-67 in OKC was higher than other cysts. Finallyinflammation may disturbe the natural trend of opotosis [P53[upwards arrow]] and facilate proliferetive ability of epithelial lining [Ki-67[upwards arrow]] in odontogenic keratocyst