Ki-67 expression in odontogenic cysts and tumors: A systematic review and meta-analysis

Abstract

Introduction: Ki-67 is a marker of cell proliferation, used as an important diagnostic marker in the pathologic differentiation of various lesions, and also is relevant for developing targeted molecular therapies. We carried out a systematic review to assess reports of the Ki-67 labeling index (LI) in odontogenic cysts and tumors. Materials and Methods: Databases were searched including Pubmed, Ovid, Web of Science, Embase and the Cochrane library. The meta-analysis was carried out based on the data from 18 studies including 608 lesions. Results: The mean values of Ki-67 LI in tumors and cysts were 4.23 (0.38) and 1.04 (0.07), respectively. Among odontogenic cysts, the highest Ki-67 LI was found in odontogenic keratocyst (3.58±0.51), and the lowest in radicular cyst (1.29±0.62%). Ki-67 LIs in all odontogenic cysts were less than 3%, except for odontogenic keratocyst. This controversial lesion seems to have a profile more similar to a tumor and a treatment plan similar to tumors may be suggested. Among benign tumors, the largest and the smallest Ki-67 LIs were seen in ameloblastoma (4.39±0.47) and adenomatoid odontogenic tumor (0.91±1.71). A significantly higher Ki-67 LI was found in ameloblastic carcinoma (17.59±2.80), and all malignant tumors demonstrated a LI of over 15.3%; when a cut-off point of 5% was set, all benign odontogenic tumors dropped below this point. Conclusion: Our findings revealed that the proliferative activity of odontogenic lesions was variable, and assessing the Ki-67 LI could be helpful in the pathologic diagnosis of histopathologically similar cysts, and could distinguish between benign and malignant tumors.