Expression of nucleostemin in odontogenic cysts and tumors.

Considering the unique clinical behavior of odontogenic cysts and tumors, this study aimed to assess the expression of nucleostemin in odontogenic cysts and tumors by immunohistochemical (IHC) staining. This retrospective study evaluated 50 samples including 13 samples of unicystic ameloblastoma (UA), 10 samples of solid ameloblastoma (SA), 10 samples of odontogenic keratocyst (OKC) and 17 samples of dentigerous cyst (DC) by IHC staining. The stained slides were evaluated under a light microscope. Number of positively stained cells for nucleostemin marker was counted in five random areas per 100 cells under x400 magnification. The labeling index (LI) for nucleostemin was calculated by dividing the number of positively stained cells by the total number of counted cells in each lesion multiplied by 100. Positive staining for nucleostemin marker was observed in 100% of SA,100% of UA, 100% of OKC and 5 samples of DC (29.4%). The LI for nucleostemin marker in SA (median: 70.5), UA (median: 50) and OKC (median: 52) samples was significantly higher than that in DC (median: 0.00) (P = .001). This study showed an increased expression of nucleostemin in ameloblastoma and OKC, which suggests that stemness may be related to development of these lesions, their invasive behavior and high rate of recurrence.