A Comparative Study of Immunohistochemical Expression of BAX Protein in Radicular Cyst and Odontogenic Keratocyst

Odontogenic keratocyst (OKC) is a developmental odontogenic cyst with an aggressive nature and high recurrence. Radicular cyst (RC) is the most common dental cyst, which may expand and cause bone loss. Bcl-2-associated X (BAX) protein acts as an apoptotic activator (pro-apoptotic), disrupts the integrity of mitochondrial membrane, and leads to the loss of outer membrane and release of cytochrome c from the inner membrane into the cytosol. Since OKC is more aggressive and has a greater tendency to recurrence than RC, the aim of this study was to assess the immunohistochemical expression of BAX protein in the epithelial lining of RC and OKC.
In this study, paraffinized blocks of 17 RCs and 17 OKCs fixed in 10% formalin were used (all OKC samples were non-inflammatory and non-syndromic). After identifying and confirming the diagnoses by reviewing the slides, the samples with sufficient length of epithelium were stained by immunohistochemistry (IHC) for BAX marker. Then, the stained cells were randomly counted in five high power fields. The cells were scored on the basis of expression as follows: (-): negative, (): less than 10%, (): between 10-25%, (): between 26-50% and (ﯯ): more than 50%. Analysis of the data was performed using SPSS 21 and Student's t-test and chi-square test.
Percentages of staining for BAX marker were 16.4±9.4 and 66.4±12.3 in the epithelial lining of OKC and RC, respectively and there was a significant difference between them (P According to the findings, lower expression of BAX protein in OKC justified its more aggressive behavior and tendency to recurrence compared to RC.