Immunolocalization of podoplanin in benign odontogenic tumours with and without ectomesenchyme.

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). 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. 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. 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.

Caetano Ados S ，Tjioe KC ，Faustino SE ，Hanemann JA ，Belone Ade F ，Soares CT ，Oliveira DT ... -  《-》

Significance of podoplanin expression in keratocystic odontogenic tumor.

Okamoto E ，Kikuchi K ，Miyazaki Y ，González-Alva P ，Oku Y ，Tanaka A ，Yoshida N ，Fujinami M ，Ide F ，Sakashita H ，Kusama K ... -  《-》

Is podoplanin expression associated with the proliferative activity of ameloblastomas?

The aim of this study was to investigate the relationship between podoplanin expression and proliferative activity of ameloblastomas and remnants of the odontogenic epithelium from dental follicles (DF) of unerupted teeth. Thirty-three paraffin-embedded ameloblastomas and thirty-two DF obtained of unerupted teeth were analyzed by immunohistochemistry using anti-human podoplanin and anti-Ki-67 antibodies. Podoplanin expression in odontogenic epithelial cells was evaluated using a scoring method, and the Ki-67 labeling index was determined by the percentage of positive odontogenic cells. All ameloblastomas displayed podoplanin expression in ameloblast-like cells of the epithelial islands. Membranous expression of podoplanin in ameloblastomas was stronger than in the remnants of odontogenic epithelium (P = 0.001). Statistically significant difference was observed between the cytoplasmic and membranous expression of podoplanin in the remnants of odontogenic epithelium (P = 0.001). The index of epithelial odontogenic proliferative activity, verified by Ki-67 expression, was higher in ameloblastomas vs remnants of odontogenic epithelium (P < 0.001). No statistically significant correlation was identified between podoplanin and the cellular odontogenic proliferative activity in meloblastomas and DF (P > 0.05). These results provide evidence that there is no connection between podoplanin immunostaining and odontogenic cellular proliferative activity and suggest a role for membranous podoplanin expression in the local invasion of ameloblastomas.

Tjioe KC ，Oliveira DT ，Soares CT ，Lauris JR ，Damante JH ... -  《-》

Podoplanin expression in human tooth germ tissues and cystic odontogenic lesions: an immunohistochemical study.

Zustin J ，Scheuer HA ，Friedrich RE 《-》

Comprehensive keratin profiling reveals different histopathogenesis of keratocystic odontogenic tumor and orthokeratinized odontogenic cyst.

Keratocystic odontogenic tumor is a cystic lesion that behaves more aggressively than other jaw cysts. One of its characteristic histologic features is a parakeratinized uniform layer of lining epithelium. A jaw cyst lined with orthokeratinized epithelium is called an orthokeratinized odontogenic cyst. These keratinized jaw cysts are thought to be separate entities, although their histopathogenesis has not been fully assessed. To better understand these lesions, we performed comprehensive immunohistochemical profiling of the keratin expression of each. Orthokeratinized odontogenic cysts expressed keratin 1, keratin 2, keratin 10, and loricrin, suggesting differentiation toward normal epidermis. Keratocystic odontogenic tumors expressed keratin 4, keratin 13, keratin 17, and keratin 19, which is a unique expression pattern reminiscent of a mucosal squamous epithelium and an epithelial appendage. In neonatal rat tooth germ, cells strongly positive for keratin 17 and keratin 19 were observed, specifically in the dental lamina, implying the origin of keratocystic odontogenic tumor. GLI2, a downstream effector of hedgehog signaling, was significantly expressed in keratocystic odontogenic tumor and basal cell carcinoma, accompanied with robust expression of keratin 17, mammalian target of rapamycin, and BCL2. The expression of these GLI2- or keratin 17-related factors was not significantly observed in orthokeratinized odontogenic cysts. These findings provide evidence to support the viewpoint that keratocystic odontogenic tumor and orthokeratinized odontogenic cyst are separate entities, and furthermore suggest their characteristic histology, pathogenesis, and biological behaviors.

Aragaki T ，Michi Y ，Katsube K ，Uzawa N ，Okada N ，Akashi T ，Amagasa T ，Yamaguchi A ，Sakamoto K ... -  《-》