Markers of proliferation and cytokeratins in the differential diagnosis of jaw cysts.

We conducted a retrospective study to analyze the histologic and immunohistochemical findings in three main types of odontogenic cyst. We studied 90 archived cystic jaw lesions: 30 dentigerous cysts, 30 keratocystic odontogenic tumors, and 30 radicular cysts. The cyst types were identified on the basis of clinical, radiologic, and histopathologic findings. Immunohistochemical analyses included staining with Ki-67, p53, epidermal growth factor receptor (EGFR), cytokeratin (CK) 8, CK14, CK17, and CK18. Cell immunopositivity was evaluated for the entire epithelium. The criteria for Ki-67 and p53 positivity were dense and/or faint nuclear staining, and cells were considered EGFR-positive if they exhibited membrane staining and/or cytoplasm staining. For the cytokeratins, cells exhibiting cytoplasm staining were considered positive. Five representative fields of each lesion were selected and identified in each of the Ki-67- and p53-stained slides. We found a statistically significant difference in the ratio of Ki-67-positive cells in the entire layer between the keratocystic odontogenic tumors and both the dentigerous cysts and the radicular cysts. A statistically significant difference was observed in the ratio of p53-positive cells between the keratocystic odontogenic tumors and the radicular cysts. Cytokeratins proved to be useful in differentiating radicular cysts from other types of cystic jaw lesions because of their CK8-positive and CK17-negative immunolabeling.