p53 protein and Ki-67 reactivity in epithelial odontogenic lesions. An immunohistochemical study

Forty-five examples of epithelial odontogenic lesions (9 ameloblastomas (AB): 13 odontogenic keratocysts (OKC): 15 dentigerous cysts (DC): 6 radicular cysts (RC): and 2 odontogenic carcinomas (OC)) were immunohistochemically analyzed for the presence of p53 protein (p53P) and proliferative activity as indicated by positivity for Ki-67 antigen. p53P+ cells, detected as dense and/or faint nuclear staining, were found in 42 of the 45 odontogenic lesions examined. Dense p53P reactivity was most commonly detected in OKC, AB and OC, with other lesions generally exhibiting only weak nuclear reactivity. Numbers of Ki-67 positive cells as well as p53P+ cells were scored semiquantitatively. Although the presence/absence of densely stained p53P+ cells was broadly related to Ki-67+ cell numbers, there were no differences in p53P+ cell numbers between lesions exhibiting differences in proliferative activity. These results suggest that overexpression of p53P, rather than increased numbers of p53P+ cells, is related to proliferation in odontogenic epithelial lesions.