Comparative evaluation of calretinin immunohistochemical expression in calcifying odontogenic cyst and ameloblastoma.

Background: Calretinin is a 29 kilodalton (KDa) calcium-binding protein that is expressed in normal and tumoral tissues. The expression of calretinin has been shown in the dental epithelium during odontogenesis and in different odontogenic cysts and tumors such as ameloblastoma. Since the epithelium of calcifying odontogenic cyst (COC) is similar to ameloblastoma and in both lesions, an arrangement of loose cells similar to stellate reticulum is seen, we aimed to investigate the comparative expression of calretinin in COC and ameloblastoma. Methods: In this observational-analytical study, 11 paraffin blocks of each lesion were examined. The immunohistochemical expression of calretinin and its severity and distribution were evaluated. Data were evaluated using SPSS version 26 and P < 0.05 was considered the level of significance. Results: Out of 11 ameloblastoma samples, calretinin staining was positive in 6 samples in the stellate reticulum-like cells and also in the lining of microcysts and macrocysts in some cases. Ameloblast like cells did not show staining. In COC samples, epithelial cells were not stained, but in 8 samples, staining was seen in the area of ghost cells. There was no significant difference in staining between ameloblastoma and COC (P = 0.33), but the difference in staining in the stellate reticulum of ameloblastoma and COC was significant. (P = 0.012). Conclusions: it is concluded that calretinin does not play a role in the pathogenesis and histogenesis of COC epithelium, but since ghost cells are caused by a degenerative process, the possibility of involving calretinin as an apoptotic factor in the formation of these cells is supported. [ABSTRACT FROM AUTHOR]