The evaluation of p16 and Ki67 immunoexpression in ameloblastomas.

In this study, we investigated the p16 and Ki67 immunoexpression in 19 ameloblastomas in order to highlight some correlations of these markers with the aggressive variants of tumors. The p16 immunoreaction was present in 90.9% of cases; the highest scores are present in the typical follicular and in the intraluminal unicystic variant, at the opposite pole being the granular cells variant. In these cases, the maximum reaction was observed at the level of the stellated reticulum cells while the lowest reaction was present at the level of cubico-cylindrical peripheral cells of the neoplastic islands. The Ki67 immunoreaction was present in all cases, the highest scores being present in the typical follicular variant, opposite being the ameloblastoma with granular cells cases and that with acanthomatous differentiation type. The immunostained cells were located predominantly at the periphery of the tumoral islands but also in the stellated reticulum cells in the central area. The p16 and Ki67 markers may be useful for distinguishing different types of ameloblastomas in terms of aggressiveness.