Immunohistochemical Expression of Calretinin in Ameloblastoma, Adenomatoid Odontogenic Tumor, and Keratocystic Odontogenic Tumor: A Comparative Study

Calretinin is expressed primarily in the central and peripheral nervous system and extensively studied in colon adenocarcinoma and mesotheliomas. Calretinin is known to be expressed in the odontogenic epithelium and odontogenic tumors. However, the role of calretinin in the pathogenesis of odontogenic tumors is yet to be confirmed. Hence, the aim of the present study was to evaluate the expression and role of calretinin in selected odontogenic tumors. The study included 30 ameloblastomas, 30 adenomatoid odontogenic tumors, and 30 keratocystic odontogenic tumors. Staining intensity, pattern, and localization of the immunopositive cells were determined. Statistical analysis was performed using Mann-Whitney U test and Kruskal-Wallis analysis of variance test. P-values <0.05 were considered to be statistically significant. Results showed that 90% ameloblastomas and 80% keratocystic odontogenic tumors were immunopositive to calretinin, whereas none of the adenomatoid odontogenic tumors showed reactivity. Intensity was higher in the ameloblastomas compared with the keratocystic odontogenic tumors. Statistically significant differences were observed when the expression of calretinin was compared, except between the ameloblastoma and keratocystic odontogenic tumor. However, the intensity of calretinin was significantly higher in the ameloblastoma when compared with the keratocystic odontogenic tumor. On the basis of these results, it is suggested that calretinin might be used as a specific immunohistochemical marker for the ameloblastomas and could play an important role in the differentiation of aggressiveness of different odontogenic tumors. Depending on the cell regulatory processes, we suggest a possible role of calretinin in the pathogenesis of ameloblastomas and have to be further studied along with other proliferative cell cycle and apoptotic markers with larger sample size.