Immunolocalization of podoplanin in benign odontogenic tumours with and without ectomesenchyme

Abstract Objectives To investigate podoplanin expression in epithelial odontogenic tumours with and without ectomesenchyme and verify the association between its immunoexpression and proliferative activity in keratocystic odontogenic tumours (KCOTS) and orthokeratinized odontogenic cysts (OOCs). Design Eight ameloblastomas, nine adenomatoid odontogenic tumours, twenty KCOTS, five OOC, one calcifying epithelial odontogenic tumour, two ameloblastic fibromas, four ameloblastic fibro-odontomas and five calcifying cystic odontogenic tumours were immunohistochemically analysed with anti-podoplanin antibody. For KCOTS and OOC, the cell proliferation index was determined with Ki-67 immunostaining and compared by Spearman correlation coefficient. Results Podoplanin was expressed in the peripheral odontogenic epithelium of most tumours. Ectomesenchyme was negative, except for odontoblasts. KCOTS exhibited positive podoplanin expression while in OOC it was absent/weak. There was statistically significant correlation ( p = 0.006) between podoplanin expression and cellular proliferation index of KCOTS and OOC. Conclusion Podoplanin seems to be related to the proliferative activity of KCOTS and may have a role in the process of local invasion of odontogenic tumours with and without ectomesenchyme.