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Avaliação da expressão da topoisomerase II alfa em tumores mamários caninos
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Authors
Abstract(s)
As neoplasias mamárias representam a neoplasia mais frequente em cadelas não esterilizadas,
assumindo grande importância em clínica veterinária. Neste estudo foram analisados
carcinomas mamários de cadela por imunohistoquímica (IHQ) para quantificação e avaliação
da expressão da Topoisomerase IIα (TOPIIA).
Objetivo: Quantificar a expressão da TOPIIA em carcinomas mamários de cadela, e
correlacionar a expressão desta com variáveis como o Ki-67, a expressão de HER-2, a
dimensão, o grau de malignidade e o tipo histológico do carcinoma.
Materiais e métodos: Cinquenta e seis carcinomas mamários e cinco amostras de tecido
mamário normal, foram submetidos a IHQ para avaliar a expressão de TOPIIA, e em cada
caso foram classificadas 1000 células de marcação negativa, fraca, moderada ou forte.
Resultados: Dos 56 tumores mamários analizados, 53,57% foram considerados positivos para
a expressão da TOPIIA. Comprovou-se a existência de correlação positiva entre a
sobreexpressão da TOPIIA e do Ki-67 (p=0,0364), e entre a sobreexpressão da proteína e
menor tempo de sobrevivência (p=0,0264). Contudo, não foi demonstrada correlação entre as
variáveis grau de malignidade, dimensão, tipo histológico do tumor e a sobreexpressão do
HER-2.
Conclusões: Este estudo sugere que a expressão da TOPIIA é maior nas células de carcinomas
mamários do que nas células de tecido mamário normal, sendo que as cadelas com tumores
classificados como positivos apresentaram menor tempo de sobrevivência, podendo este
marcador ser considerado como fator de prognóstico. Contudo é indispensável a realização de
mais estudos sobre este assunto, que contribuam para um maior conhecimento da importância
desta proteína em oncologia veterinária assim como em medicina humana.
ABSTRACT- Topoisomerase IIα expression in canine mammary tumors - Mammary tumors are the most common neoplasm in intact female dogs; therefore they are extremely important in veterinary clinic. The aim of this study was to assess Topoisomerase IIα (TOPIIA) expression in canine mammary carcinomas by immunohistochemistry (IHC). Objective: To quantify the expression of TOPIIA in mammary carcinomas in female dogs, and correlate its expression with other factors such as Ki-67, HER-2, tumor size, histologic grade and type. Patients and methods: Fifty six mammary carcinomas and five samples of normal breast tissue were analyzed by IHC, and in each case, 1000 cells were classified accordingly to their labeling intensity: negative, weak, moderate or strong. Results: 53,57% of the 56 mammary tumors were considered to have increased expression of TOPIIA. A positive correlation between positive TOPIIA tumors and Ki-67 overexpression (p=0,0364) and an inferior survival time (p=0,0264) was found. However, there was no correlation between TOPIIA expression and histologic grade, tumor size and HER-2 positivity. Conclusions: This study supports the idea that mammary tumors cells have higher TOPIIA expression than normal breast tissue cells, and animals with those considered to be positive tumors, have a lower survival time, which can indicate that TOPIIA expression may be considered as a prognostic factor. It is however important that more studies be performed, to assess the importance of this protein in veterinary oncology as well in human medicine.
ABSTRACT- Topoisomerase IIα expression in canine mammary tumors - Mammary tumors are the most common neoplasm in intact female dogs; therefore they are extremely important in veterinary clinic. The aim of this study was to assess Topoisomerase IIα (TOPIIA) expression in canine mammary carcinomas by immunohistochemistry (IHC). Objective: To quantify the expression of TOPIIA in mammary carcinomas in female dogs, and correlate its expression with other factors such as Ki-67, HER-2, tumor size, histologic grade and type. Patients and methods: Fifty six mammary carcinomas and five samples of normal breast tissue were analyzed by IHC, and in each case, 1000 cells were classified accordingly to their labeling intensity: negative, weak, moderate or strong. Results: 53,57% of the 56 mammary tumors were considered to have increased expression of TOPIIA. A positive correlation between positive TOPIIA tumors and Ki-67 overexpression (p=0,0364) and an inferior survival time (p=0,0264) was found. However, there was no correlation between TOPIIA expression and histologic grade, tumor size and HER-2 positivity. Conclusions: This study supports the idea that mammary tumors cells have higher TOPIIA expression than normal breast tissue cells, and animals with those considered to be positive tumors, have a lower survival time, which can indicate that TOPIIA expression may be considered as a prognostic factor. It is however important that more studies be performed, to assess the importance of this protein in veterinary oncology as well in human medicine.
Description
Dissertação de Mestrado Integrado em Medicina Veterinária
Keywords
Tumor mamário carcinoma mamário topoisomerase IIα imunohistoquímica antraciclina prognóstico mammary tumor mammary carcinoma topoisomerase IIα immunohistochemistry anthracycline prognostic
Pedagogical Context
Citation
Valdevino, H.R.C. (2018). Avaliação da expressão da topoisomerase II alfa em tumores mamários caninos
Publisher
Universidade de Lisboa, Faculdade de Medicina Veterinária