Fatores histopatológicos e moleculares em retinoblastomas enucleados

• Ano de defesa: 2013
• Autor(a) principal: Salustiano, Luciana Ximenes
• Orientador(a): Ávila, Marcos Pereira de
• Banca de defesa: Ávila, Marcos Pereira de, Carneiro, Fabiana P., Saddi, Vera A., Mendonça, Elismauro F. de, Cruvinel, Davi Isaac
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Goiás
• Programa de Pós-Graduação: Programa de Pós-graduação em Ciências da Saúde (FM)
• Departamento: Faculdade de Medicina - FM (RG)
• País: Brasil
• Palavras-chave em Português: Retinoblastoma; Histopatológico; Munoistoquímica; P16; Ki67; VEGF; Retinoblastomas; Histopathological characteristics; Immunohistochemistry
• Área do conhecimento CNPq: CIENCIAS DA SAUDE::MEDICINA
• Link de acesso: http://repositorio.bc.ufg.br/tede/handle/tede/3247

Retinoblastoma (RB) is the malignant neoplasm of embryonic neural retinal cells and is the most common intraocular tumor of childhood. Early diagnosis associated with modern methods of treatment resulted in increased survival rate of patients with retinoblastoma. However, in those cases whose diagnosis is delayed and in untreated cases, the disease is invariably fatal. The knowledge of the molecular and histopathological features of retinoblastomas can influence the choice of treatment and benefit the prognosis of these tumors. Thus, the objectives of this study are to evaluate the main histopathological and molecular characteristics of retinoblastomas, including the evaluation of p16, Ki67 and VEGF protein expression, as well as the potential role of such molecules as prognostic markers in the retinoblastomas. Fifty-seven cases of RB were evaluated in enucleated eyes at Hospital Araújo Jorge, in Goiânia, in the period of 1998 to 2011. Clinical data were collected from the respective medical files and the cases were reviewed for analysis of histopathological aspects. The expression of Ki67, p16 and VEGF was assessed by immunohistochemistry, using specific antibodies and a detection system associated with polymers. The results were analyzed by descriptive statistics and categorical variables by chi-square test and Fisher exact test, when necessary. Ki67 overexpression was observed in 28% of cases, characterizing the retinoblastomas with high rate of cellular proliferation, while the p16 overexpression was observed in 42% of retinoblastomas evaluated. Significant associations were observed between the overexpression of these proteins and histopathological characteristics of worse prognosis, including invasion of the optic nerve, choroid, sclera and anterior chamber of the eye, as well as to a lower degree of cellular differentiation. VEGF expression was extensively observed in all retinoblastoma cases, independent of the histopathological aspects of the tumors. The associations observed in this study between tumor aggressive histopathological aspects and Ki67 and p16 overexpression, indicate the use of these markers in determining the prognosis of retinoblastomas. On the other hand, the high angiogenic potential of retinoblastomas, translated by diffuse VEGF expression in all cases analyzed in this study, raises new investigations on the use of anti-angiogenic drugs in the treatment of retinoblastomas.