A Comparative Study of Cytokeratin 7 Expression in Dentigerous Cyst and Radicular Cyst by Immunohistochemical Method

It is difficult to identify the type of odontogenic cyst in some patients. Evidence shows that difference in expression level of different cytokeratins can be helpful for detection and identification of odontogenic cysts. The aim of this study was to investigate the cytokeratin 7 (CK7) expression in radicular cysts and dentigerous cysts.

In this cross-sectional study, 20 samples of radicular cysts and 20 samples of dentigerous cysts (10 inflammatory, 10 non-inflammatory) were selected from the archives of the Oral Pathology Department of Isfahan Dental School, which had been obtained by excisional biopsy. Age and gender of patients, and loca-tion of lesion were extracted from patient records. Immunohistochemical (IHC) stain-ing for CK7 was performed and the expression level of this marker was determined based on the SID index. Data were statistically analyzed by the Mann-Whitney, Kruskal-Wallis, Chi-square, Fisher's exact, and t tests using SPSS ver-sion 24 at 0.05 level of significance.

The two groups had no significant difference regarding the mean age (P=0.785), gender (P=0.490), or lesion location (P=0.172). There was a significant dif-ference between radicular and dentigerous cysts in CK7 expression (P=0.003), and the pattern of staining (P=0.028). No significant difference was found between inflamma-tory and non-inflammatory dentigerous cysts based on CK7 expression (P=062).

Expression of CK7 may be useful for differentiation of dentigerous cyst from radicular cyst.