ING3 and ING4 immunoexpression and their relation to the development of benign odontogenic lesions.

The Inhibitor of Growth (ING) gene family is a group of tumor suppressor genes that play important roles in cell cycle control, senescence, DNA repair, cell proliferation, and apoptosis. However, inactivation and downregulation of these proteins have been related in some neoplasms. The present study aimed to evaluate the immunohistochemical profiles of ING3 and ING4 proteins in a series of benign epithelial odontogenic lesions. METHODS: The sample comprised of 20 odontogenic keratocysts (OKC), 20 ameloblastomas (AM), and 15 adenomatoid odontogenic tumors (AOT) specimens. Nuclear and cytoplasmic immunolabeling of ING3 and ING4 were semi-quantitatively evaluated in epithelial cells of the odontogenic lesions, according to the percentage of immunolabelled cells in each case. Descriptive and statistics analysis were computed, and the p-value was set at 0.05. RESULTS: No statistically significant differences were found in cytoplasmic and nuclear ING3 immunolabeling among the studied lesions. In contrast, AOTs presented higher cytoplasmic and nuclear ING4 labeling compared to AMs (cytoplasmic p-value = 0.01; nuclear p-value < 0.001) and OKCs (nuclear p-value = 0.007). CONCLUSION: ING3 and ING4 protein downregulation may play an important role in the initiation and progression of more aggressive odontogenic lesions, such as AMs and OKCs.

ING3 and ING4 immunoexpression and their relation to the development of benign odontogenic lesions

Abstract The Inhibitor of Growth (ING) gene family is a group of tumor suppressor genes that play important roles in cell cycle control, senescence, DNA repair, cell proliferation, and apoptosis. However, inactivation and downregulation of these proteins have been related in some neoplasms. The present study aimed to evaluate the immunohistochemical profiles of ING3 and ING4 proteins in a series of benign epithelial odontogenic lesions. Methods: The sample comprised of 20 odontogenic keratocysts (OKC), 20 ameloblastomas (AM), and 15 adenomatoid odontogenic tumors (AOT) specimens. Nuclear and cytoplasmic immunolabeling of ING3 and ING4 were semi-quantitatively evaluated in epithelial cells of the odontogenic lesions, according to the percentage of immunolabelled cells in each case. Descriptive and statistics analysis were computed, and the p-value was set at 0.05. Results: No statistically significant differences were found in cytoplasmic and nuclear ING3 immunolabeling among the studied lesions. In contrast, AOTs presented higher cytoplasmic and nuclear ING4 labeling compared to AMs (cytoplasmic p-value = 0.01; nuclear p-value < 0.001) and OKCs (nuclear p-value = 0.007). Conclusion: ING3 and ING4 protein downregulation may play an important role in the initiation and progression of more aggressive odontogenic lesions, such as AMs and OKCs.

Resumo Objetivos: A família dos Genes Inibidores de Crescimento (ING) é um grupo de genes supressores tumorais que desempenham papéis importantes no controle do ciclo celular, na senescência, no reparo do DNA, na proliferação celular e na apoptose. No entanto, a inativação e a regulação negativa dessas proteínas têm sido relacionadas em algumas neoplasias. O objetivo do presente estudo foi avaliar o perfil imuno-histoquímico das proteínas ING3 e ING4 em uma série de lesões odontogênicas epiteliais benignas. Métodos: A amostra foi composta por espécimes de 20 ceratocistos odontogênicos (CO), 20 ameloblastomas (AM) e 15 tumores odontogênicos adenomatoides (TOA). A imunoexpressão nuclear e citoplasmática de ING3 e ING4 foram avaliadas semi-quantitativamente nas células epiteliais das lesões odontogênicas, de acordo com a porcentagem de células imunomarcadas em cada caso. As análises descritivas e estatísticas foram computadas, e o valor de p estabelecido foi de 0,05. Resultados: Não foram encontradas diferenças estatisticamente significativas na imunoexpressão citoplasmática e nuclear de ING3 entre as lesões estudadas. Em contrapartida, os TOAs apresentaram maior marcação citoplasmática e nuclear de ING4 em comparação aos AMs (valor de p citoplasmático=0,01; valor de p nuclear <0,001) e COs (valor nuclear de p=0,007). Conclusão: A regulação negativa das proteínas ING3 e ING4 pode desempenhar um papel importante na iniciação e na progressão de lesões odontogênicas mais agressivas, como AMs e COs.