Podoplanin expression in ameloblastomas and dental follicles of unerupted teeth: comparative estudy with Ki-67 expression

Author(s)

Kellen Cristine Tjioe

• Document type: Master's Dissertation
• Press: Bauru.
• Institution: Universidade de São Paulo (USP). Faculdade de Odontologia de Bauru (FOB/SDB)
• Defense date: 2011-04-25

Examining board members

Jose Humberto Damante; Denise Tostes Oliveira; Décio dos Santos Pinto Júnior

• Advisor: Jose Humberto Damante

Abstract

The association between podoplanin and cellular proliferative activity has been demonstrated but is still source of debate. The aim of this study was to investigate the expression of podoplanin in ameloblastomas and remnants of odontogenic epithelium (ROE) from dental follicles of unerupted teeth and verify the relation between the podoplanin expression and proliferative activity of the odontogenic cells. Thirty-three patients submitted to the incisional biopsy or resection of ameloblastoma and 32 patients submitted to the extraction of unerupted tooth were selected for analysis. Archived paraffin-embedded ameloblastomas and dental follicles specimens were sectioned and stained with anti-human podoplanin and anti-Ki-67 antibodies. The podoplanin expression by odontogenic epithelial cells was evaluated using a score method and the Ki-67 labelling index was obtained by the percentage of positive odontogenic cells (at least 500 cells/ameloblastoma and all ROE cells). All ameloblastomas showed podoplanin expression in ameloblast-like cells of the epithelial islands. Weak or absent immunostaining was observed in the central cells resembling stellate reticulum. Podoplanin expression in ROE was mainly found in the cells in contact with the connective tissue. Membranous expression of podoplanin in ameloblastomas was stronger than its expression in ROE (!=0.001). Statistically significant difference between cytoplasmic and membranous expression of podoplanin in ROE was observed (!=0.001). The index of cellular odontogenic proliferative activity, verified by Ki-67 expression, was highest in ameloblastomas when compared with ROES (!<0.001). No statistically significant correlation between podoplanin and cellular odontogenic proliferative activity in ameloblastomas and dental follicles was found (!>0.05). These results support the evidence that there is no connection between podoplanin expression and odontogenic cellular proliferative activity in ameloblastomas and reinforce that the exact role of this protein in benign odontogenic tumor needs to be elucidated. (AU)

• FAPESP's process: 09/12813-0 - Expression of podoplanin in ameloblastomas and dental follicles of unerupted teeth: Comparative study with the Ki-67 expression
• Grantee: Kellen Cristine Tjioe
• Support Opportunities: Scholarships in Brazil - Master