Molecular alterations in the development and progression of odontogenic tumors

Insight into the molecular pathogenesis of odontogenic lesions

BACKGROUND

Odontogenic tumors, derived from epithelial, ectomesenchymal, and/or mesenchymal elements of the tooth-forming apparatus, constitute a heterogeneous group of lesions, including hamartomas, benign and malignant neoplasms with metastatic capabilities.

HIGHLIGHT

This review provides a comprehensive overviewof the pathogenesis of odontogenic tumors and explains the associated molecular events in the context of hallmarks of cancer established by Hanahan D and Weinberg RA. Diagrammatic representations depicted in the article would facilitate easier understanding.

CONCLUSION

A better understanding of the pathogenesis of the lesions may assist in determining patient's prognosis and devising better targeted therapeutic treatment, thus, reducing the morbidity and mortalityof patients.

Immunohistochemical assessment of ATG7, LC3, and p62 in ameloblastomas

BACKGROUND

To investigate the roles of autophagy in tumorigenesis, cytodifferentiation, and prognosis of odontogenic tumors, we analyzed the immunohistochemical expression of ATG7, LC3, and p62 in odontogenic tissues.

METHODS

Tissue specimens of nine dental follicles and 69 ameloblastomas were immunohistochemically examined with antibodies against ATG7, LC3, and p62.

RESULTS

Immunohistochemical reactivity for ATG7, LC3, and p62 was detected in many odontogenic epithelial cells and several endothelial cells and fibroblasts in dental follicles and ameloblastomas. ATG7 reactivity in ameloblatomas was significantly higher than that in dental follicles. Expression of ATG7, LC3, and p62 was found markedly in neoplastic cells near the basement membrane rather than central polyhedral cells in ameloblastomas. Reactivity for these molecules was significantly higher in unicystic ameloblastomas than in solid ameloblastomas. Granular cells in granular cell ameloblastomas showed obvious reactivity for the autophagy- related molecules, and LC3 reactivity in granular cell ameloblastomas was significantly higher than in other ameloblastoma variations. Recurrent ameloblastomas showed significantly lower reactivity of LC3 and p62 than primary ameloblastomas.

CONCLUSIONS

Expression of ATG7, LC3, and p62 in dental follicles and ameloblastomas suggests that autophagy regulation might be affected by microenvironment alterations during tumorigenesis. The molecular machinery for autophagy is possibly involved in tissue architecture, neoplastic cell differentiation, and prognosis of the benign epithelial odontogenic tumor.