Proliferating cell nuclear antigen and Ki67 immunoreactivity in ameloblastomas

Objective. This study used proliferating cell nuclear antigen (PCNA) and Ki67 to evaluate and compare the in situ proliferative activity of (1) solid and multicystic and (2) unicystic ameloblastomas in an attempt to provide a scientific basis for any differences in biologic behavior that exists between these 2 groups of lesions. Study design. Twenty archival tissue sections, 10 of primary unicystic and 10 of solid and multicystic ameloblastomas, were immunohistochemically stained with PCNA and Ki67 antisera. Immunoreactivity was evaluated by the counting of cells, and the data obtained were statistically analyzed. Results. The results showed that cellular proliferative activity varied within the ameloblastoma types. The unicystic ameloblastomas showed statistically significantly higher PCNA and Ki67 labeling indices than the solid and multicystic variant. Conclusion. There appears, therefore, to be no correlation between proliferative activity as shown by these proteins and reported biologic behavior.