Expressão imunohistoquímica da iNOS em melanomas orais de cães
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2019-10-10
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Os tumores melanocíticos podem apresentar um caracter maligno, invasivo e com potencial metastático, e neste contexto, justifica-se o estudo imunohistoquímico da expressão da iNOS (óxido nítrico sintetase) para ampliar o conhecimento do comportamento e do microambiente que envolve estas neoplasias. A sintetase do óxido nítrico, que catalisa a produção de óxido nítrico, é uma importante molécula envolvida na sinalização celular, e está associada a muitos processos fisiológicos e patológicos como a inflamação e o cancro. A sua deteção nos tecidos é usada como indicador dos níveis de óxido nítrico. Os estudos acerca da importância do óxido nítrico nos tumores são ainda pouco consensuais e por vezes contraditórios. Sendo o melanoma um paradigma para o estudo da imunologia tumoral, os autores efetuaram um estudo retrospetivo com base em quinze melanomas orais provenientes do Laboratório de Anatomia Patológica da Universidade de São Paulo-Brasil. De cada animal foram registados os dados referentes à identificação (idade, género e raça) e os dados referentes ao tumor (tamanho, localização e presença de metástases) tendo sido feita, posteriormente, uma avaliação das lesões em preparações coradas com hematoxilina-eosina, relativamente aos seguintes parâmetros histopatológicos previamente definidos: atividade juncional; grau de atipia nuclear; tipo celular; infiltrado celular, presença de células gigantes, de células tumorais intravasculares, de ulceração ou necrose; grau de pigmentação celular; estroma e índice mitótico. A expressão da iNOS foi efetuada pelo método da estreptavidina biotina peroxidase. A execução deste método consiste na incubação do anticorpo primário, seguido de um anticorpo secundário biotinilado e do complexo streptavidina-biotina conjugado com a enzima horseradish peroxidase (HRP). Para cada caso, foram avaliados vários parâmetros histopatológicos, os tumores foram categorizados em dois grupos: 0 – negativos (onde se incluíram os tumores negativos ou com grau 1 de extensão) e 1 – positivos (onde se incluíram os graus 2 e 3, independentemente da intensidade de marcação). O Grau de atipia e o tipo celular associaram-se com expressão de iNOS, com um nível de significância de (p=0,044) e (p=0,047) respetivamente. Assim, os tumores com atipia moderada são todos negativos para a iNOS. Já a maioria dos tumores com elevada atipia são, em geral, positivos para a iNOS. Em relação ao tipo celular, os tumores de células redondas, dois são positivos, enquanto os tumores com células de morfologia mista são, em geral, negativos para este biomarcador.
Melanocytic tumors appear malignant, invasive and potentially metastatic in character; in this context, the immunohistochemical study of the aspect of iNOS (nitric oxide synthetase) is justified in order to expand our knowledge of the behavior and the microenvironment that surrounds these neoplasms. Nitric oxide synthetase, which catalyzes the production of nitric oxide, is an important molecule involved in cell signaling, and is associated with many physiological and pathological processes such as inflammation and cancer. Its detection in tissues is used as an indicator of nitric oxide levels. Studies of the importance of nitric oxide in tumors are still not very consensual and are often contradictory. Since melanoma is a paradigm for the study of tumor immunology, the authors performed a retrospective study based on fifteen oral melanomas from the Laboratory of Pathological Anatomy of the University of São Paulo-Brasil. Data from each animal was recorded including identifying markers (age, gender, and breed), and tumor data (size, location, and presence of metastases). An evaluation of the lesions was performed using hematoxylin-eosin stained preparations with respect to the following previously defined histopathological parameters: junctional activity, degree of nuclear atypia, cell type, cellular infiltrate, and presence of giant cells, intravascular tumor cells, ulceration or necrosis, degree of cellular pigmentation, stroma, and mitotic index. The aspect of iNOS was effected by the streptavidin biotin peroxidase method. This method is performed by incubating the primary antibody, followed by a biotinylated secondary antibody and the horseradish peroxidase (HRP) conjugated streptavidinbiotin complex. For each case, several histopathological parameters were evaluated; tumors were categorized into two groups: 0 - negative (where negative tumors were included or 1 degree - positive tumors) and 1 - positive tumors (including degrees 2 and 3, irrespective of the degree of labeling). The degree of atypia and the cell type were statistically significant, with a significance level of (p = 0.044) and (p = 0.047) respectively. The authors found that tumors with moderate atypia are all negative for iNOS, but most tumors with high atypia are positive for iNOS. With regard to the cell type; in tumors with round cells, two are positive, while tumors with cells of mixed morphology are generally negative for this biomarker
Melanocytic tumors appear malignant, invasive and potentially metastatic in character; in this context, the immunohistochemical study of the aspect of iNOS (nitric oxide synthetase) is justified in order to expand our knowledge of the behavior and the microenvironment that surrounds these neoplasms. Nitric oxide synthetase, which catalyzes the production of nitric oxide, is an important molecule involved in cell signaling, and is associated with many physiological and pathological processes such as inflammation and cancer. Its detection in tissues is used as an indicator of nitric oxide levels. Studies of the importance of nitric oxide in tumors are still not very consensual and are often contradictory. Since melanoma is a paradigm for the study of tumor immunology, the authors performed a retrospective study based on fifteen oral melanomas from the Laboratory of Pathological Anatomy of the University of São Paulo-Brasil. Data from each animal was recorded including identifying markers (age, gender, and breed), and tumor data (size, location, and presence of metastases). An evaluation of the lesions was performed using hematoxylin-eosin stained preparations with respect to the following previously defined histopathological parameters: junctional activity, degree of nuclear atypia, cell type, cellular infiltrate, and presence of giant cells, intravascular tumor cells, ulceration or necrosis, degree of cellular pigmentation, stroma, and mitotic index. The aspect of iNOS was effected by the streptavidin biotin peroxidase method. This method is performed by incubating the primary antibody, followed by a biotinylated secondary antibody and the horseradish peroxidase (HRP) conjugated streptavidinbiotin complex. For each case, several histopathological parameters were evaluated; tumors were categorized into two groups: 0 - negative (where negative tumors were included or 1 degree - positive tumors) and 1 - positive tumors (including degrees 2 and 3, irrespective of the degree of labeling). The degree of atypia and the cell type were statistically significant, with a significance level of (p = 0.044) and (p = 0.047) respectively. The authors found that tumors with moderate atypia are all negative for iNOS, but most tumors with high atypia are positive for iNOS. With regard to the cell type; in tumors with round cells, two are positive, while tumors with cells of mixed morphology are generally negative for this biomarker
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Dissertação de Mestrado Integrado em Medicina Veterinária
Palavras-chave
Melanoma , Cães