Expression of p63 in tooth germ, dentigerous cyst and ameloblastoma

To assess the role of p63, a p53 homolog, in the cytodifferentiation (odontogenesis) and oncogenesis of odontogenic epithelium.

The present study aimed to compare the expression pattern of p63 in the epithelium of tooth germ, dentigerous cyst (DC) and ameloblastoma (AB).

Tissue specimens of thirty tooth germs, thirty ABs and thirty DCs were examined by immunohistochemistry for the expression of p63. Results: p63 labeling index (LI) was observed in descending order in epithelial cells of ABs, tooth germs and DCs. p63 LI was statistically nonsignificant among all the three groups. ABs revealed the highest p63 expression, but, surprisingly, tooth germs showed higher expression than DCs.

p63 plays a role in the cytodifferentiation and proliferation of odontogenic epithelial cells irrespective of the tissue (normal developing or lesional tissue). This implies that p63 cannot be used as a diagnostic marker. However, our results indicate p63 overexpression as a mark of increased proliferation. Thus, it can be stipulated that p63 can be used as a prognostic marker in odontogenic lesions with more aggressive and invasive phenotype. Our results also suggest the differential function of p63 in both developing and lesional odontogenic tissues, which, however, depends on p63 isoform predominantly being expressed. Therefore, identification of p63-predominant isoform in a particular lesion is more important than the presence or absence of p63. Consequently, we suggest the performance of polymerase chain reaction analysis along with immunohistochemical evaluation in further studies.