Although
ameloblastoma and
adenomatoid odontogenic tumor (AOT) belong to the same group according to the World Health Organization, they show different
biologic behaviors.
PCNA, an amplifier of cell proliferation, and p53, a
tumor suppressor protein, are overexpressed in some odontogenic lesions. The purpose of this study was to immunohistochemically evaluate the expression of p53 and
PCNA to clarify the possible role of these
proteins in different behaviors of
ameloblastoma and AOT. The immunohistochemical expression of
PCNA and p53 was determined in 30 solid
ameloblastomas and 12 AOTs. Statistical tests including one-way ANOVA, t-test, chi-square, Mann-Whitney U and Kendall were used to analyze the data. All tissue sections (except one specimen of plexiform
ameloblastoma) exhibited immunoexpression for p53.
PCNA was expressed in all specimens. There was no significant difference in
PCNA expression between
ameloblastomas and AOTs (P > 0.05). For p53, there was no statistical difference between subtypes of
ameloblastomas (P > 0.05), whereas statistical differences were observed between
ameloblastomas and AOTs (P < 0.001). There was no statistical difference in
PCNA intensity of staining between
ameloblastomas and AOTs (P > 0.05), whereas the p53 intensity in
ameloblastomas was stronger than AOTs (P < 0.05). Positive correlation between
PCNA and p53 was observed. We concluded that
PCNA overexpression is not responsible for the difference in clinical behavior of these two lesions, whereas the expression of p53 in
ameloblastoma may explain the more aggressive nature of this
tumor compared with AOT.