Immunohistochemical assessment of stem cell-related Sox2 and Klf4 in ameloblastomas

We aimed to investigate the potential roles of sex-determining region Y-related high mobility group-box 2 (Sox2) and Krüppel-like factor 4 (Klf4), two stem cell-related molecules, in odontogenic tissues. Immunohistochemical reactivity to Sox2 and Klf4 was examined in 10 dental follicle and 54 ameloblastoma specimens. The association between these molecules and clinical variables was analyzed in ameloblastoma cases. Dental follicles showed immunoreactivity to Sox2 and Klf4 predominantly in the dental lamina. In ameloblastomas, Sox2 and Klf4 expression was detected in 48 of the 54 cases, and was predominantly localized in neoplastic cells adjacent to the basement membrane. Sox2 showed substantially higher expression in dental follicles than in ameloblastomas. Granular cell ameloblastomas presented lower levels of Sox2 and Klf4 than acanthomatous ameloblastomas. Moreover, immunoreactivity of ameloblastomas to Sox2 and Klf4 was slightly higher in recurrent cases than in non-recurrent cases. The differential expression patterns of Sox2 and Klf4 in dental follicles and ameloblastomas indicate that these transcription factors may be involved in the regulation of odontogenic tissues. As these transcription factors are associated with cell proliferation and differentiation in the odontogenic epithelium, they may contribute to tumorigenesis or disease prognosis.