Matrix metalloproteinase 9 expression in canine mammary carcinomas

Mammary neoplasms are among the most common canine tumors, with high risk of invasion and metastasis. Important steps for these events are the loss of cell adhesion to the main tumor mass and extracellular matrix degradation. Matrix metalloproteinases (MMPs) are proteolytic enzymes containing zinc, which are capable of degrading and remodeling the surrounding extracellular matrix, facilitating these events. Involvement of MMPs has been demonstrated in many pathological processes, as well as in human and canine tumors, which has been related to malignancy and prognosis. The aim of this study was to characterize the immunohistochemical expression of matrix metalloproteinase 9 (MMP-9) in canine mammary gland tumors, as well as to verify its relation with the different histologic patterns. Thirty-one of the 41 tumors (75.61%) were positive. Twenty-two samples (70.97%) had diffuse cytoplasmic immunostaining and 9 (29.03%) had a finely granular pattern. Immunostaining intensity was strong in 21 (67.74%) tumors and weak in 10 (32.26%). No statistically significant differences were found between anaplastic carcinomas, carcinomas in a mixed tumor and simple carcinomas regarding positivity (p=0.9707), intensity (p=0.5386) and staining pattern (0.6135); between solid carcinomas and simple papillary carcinomas for positivity (p=0,7333), intensity (p=0.7333) and staining pattern (p=0.3037); or betweensolid carcinomas and simple tubular and papillary carcinomas for positivity (p=0.9682), intensity (p=0.8450) and staining pattern (p=0.5068). MMP-9 was detected with variable intensity and morphological patterns of cytoplasmic staining. However significant statistic differences were not found between the histological types or histopathological grades.

Matrix metalloproteinase 9 expression in canine mammary carcinomas

Mammary neoplasms are among the most common canine tumors, with high risk of invasion and metastasis. Important steps for these events are the loss of cell adhesion to the main tumor mass and extracellular matrix degradation. Matrix metalloproteinases (MMPs) are proteolytic enzymes containing zinc, which are capable of degrading and remodeling the surrounding extracellular matrix, facilitating these events. Involvement of MMPs has been demonstrated in many pathological processes, as well as in human and canine tumors, which has been related to malignancy and prognosis. The aim of this study was to characterize the immunohistochemical expression of matrix metalloproteinase 9 (MMP-9) in canine mammary gland tumors, as well as to verify its relation with the different histologic patterns. Thirty-one of the 41 tumors (75.61%) were positive. Twenty-two samples (70.97%) had diffuse cytoplasmic immunostaining and 9 (29.03%) had a finely granular pattern. Immunostaining intensity was strong in 21 (67.74%) tumors and weak in 10 (32.26%). No statistically significant differences were found between anaplastic carcinomas, carcinomas in a mixed tumor and simple carcinomas regarding positivity (p=0.9707), intensity (p=0.5386) and staining pattern (0.6135); between solid carcinomas and simple papillary carcinomas for positivity (p=0,7333), intensity (p=0.7333) and staining pattern (p=0.3037); or betweensolid carcinomas and simple tubular and papillary carcinomas for positivity (p=0.9682), intensity (p=0.8450) and staining pattern (p=0.5068). MMP-9 was detected with variable intensity and morphological patterns of cytoplasmic staining. However significant statistic differences were not found between the histological types or histopathological grades.(AU)

Análise de sobrevida e fatores prognósticos de cães com mastocitoma cutâneo / Survival analyses and prognostic markers in canine cutaneous mast cell tumors

O mastocitoma é a neoplasia cutânea maligna de maior frequência em cães. Apesar do estudo e do desenvolvimento de diversos marcadores prognósticos na tentativa de prever o comportamento biológico deste tipo de neoplasia, a graduação histológica continua sendo utilizada como principal delineador prognóstico para os animais acometidos, mesmo não conseguindo prever o comportamento de mastocitomas de diferenciação intermediária. Diferentes marcadores de proliferação e atividade celular vêm sendo testados com resultados promissores, entretanto, em sua maioria, demandam técnicas específicas de coloração e imuno-histoquímica que, ainda hoje, são de alto custo e muitas vezes não estão facilmente disponíveis. O índice mitótico é um método indireto de mensuração da atividade proliferativa celular, que pode ser contabilizado em uma lâmina comum de avaliação histológica e estudos vêm determinando-o como importante marcador prognóstico para o mastocitoma canino. Dada a recente publicação sugerindo nova graduação em dois graus (alto e baixo) e indisponibilidade das técnicas específicas utilizadas na determinação de outros fatores prognósticos, objetivou-se avaliar o poder prognóstico das diferentes classificações, associando-as à sobrevida destes animais e comparando com o índice mitótico. Apesar de isoladamente ambas as classificações histológicas apresentarem associação com a sobrevida (P<.001) dos animais acometidos, na análise multifatorial nenhuma foi significativamente associada com a sobrevida (P>0,05). O índice mitótico foi o fator prognóstico mais confiável para sobrevida, independente do ponto de corte utilizado (P<0,05), principalmente para os mastocitomas grau 2 de Patnaik et al. (1984), que apresentam comportamento biológico variado, sendo também associado à ocorrência de recidivas, tanto locais como distantes, e de síndromes paraneoplásicas (P<0,05). Conclui-se ser o índice mitótico o fator prognóstico mais significante, na ausência de técnicas específicas mais avançadas. Preconiza-se seu uso associado às graduações histológicas, visando maior poder prognóstico.(AU)

Mast cell tumor (MCT) is the most common malignant cutaneous neoplasm in dogs. Even with several prognostic markers being studied, in attempt to previse the biological behavior of these tumors, the histological grading is still commonly used to predict behavior, however, it is not significant to predict intermediately differentiated MCT behavior. Different prognostic and cell proliferation markers are being tested with promising results however, the majority of then requires specific staining and immunohistochemical techniques that even nowadays are expensive and not suitable for all veterinarians. Mitotic index is an indirect measure of cell proliferation and it can be established in a common histological microscope slide, and studies indicate it as an important prognostic marker for MCT in dogs. Given the recent publication of the novel two-tier histologic grading system, this study objective to evaluate the prognostic value of the different grading systems associating with survival and compare it with the mitotic index. Even though both grading systems associate with survival in the univariable analyses (P<.001), at the multivariable analyses neither was associated with survival (P>0,05), and the mitotic index was the most significant prognostic factor for survival, regardless of the cut-off point used (P<0,05), especially when Patnaik grade 2 tumors with unpredictable biological behavior were analyzed. The mitotic index was also significantly associated with both local and distant reccurence and paraneoplastic syndrome. In this study, mitotic index was the most significant prognostic factor, in the absence of specific staining and advanced immunohistochemical techniques, and its use is indicated in association with both histological grading system, aiming to add higher prognostic value possible.(AU)

Avaliação de marcadores imunohistoquímicos de resistência à múltiplas drogas nos carcinomas mamários em felinos

O tumor mamário é a terceira neoplasia mais incidente na espécie felina, cerca de 95% dos tumores mamários são malignos e a doença tende a apresentar um comportamento altamente agressivo. O tratamento de eleição para essas neoplasias é a cirurgia radical, seguida de quimioterapia adjuvante. Ainda assim, a mortalidade associada à recidiva tumoral e/ou metástases é frequente, indicando uma falha nos procedimentos terapêuticos, mais precisamente na quimioterapia. Assim, o presente estudo teve como objetivo determinar a imunoexpressão de proteínas associadas à resistência à múltiplas drogas nos carcinomas mamários em felinos, correlacionando-as com aspectos clínico-patológicos e sobrevida. Participaram deste estudo 46 gatas atendidas e operadas em hospitais veterinários públicos e particulares. Os tumores foram submetidos à análise histopatológica, seguida pela análise imunohistoquímica para detecção da glicoproteína P (GlicoP), proteína relacionada a resistência de pulmão (LRP) e metalotioneína (MT). Os parâmetros clinicopatológicos foram correlacionados com a sobrevida pelo teste de Log-rank (P<0,05). A presença de metástase à distância, estadiamento clinico, tipo de cirurgia adotada e o uso de quimioterapia adjuvante apresentaram associação com a sobrevida. A GlicoP e a LRP demonstraram, respectivamente, imunoexpressão intensa em 45,6% e 47,8% dos casos; enquanto a MT apresentou imunoexpressão discreta em 45,7% dos casos. Porém, todas as proteínas foram expressas em algum grau em todas as amostras. Foi encontrada correlação positiva entre a GlicoP e a graduação histológica (P=0,049), e da MT com os subtipos moleculares (P=0,023). Porém, não houve correlação de nenhuma das proteínas analisadas com a sobrevida. Estes dados indicam a presença de múltiplas proteínas de resistência aos antineoplásicos em carcinomas mamários em felinos, além de sua correlação com o alto grau de malignidade destas neoplasias. Apesar de não haver correlação com a sobrevida, estes marcadores podem indicar um pior prognóstico, além de uma possível baixa resposta à quimioterapia adjuvante.

Mammary tumors are ranked as the third neoplasm with most incidents within the feline species. Around 95% of the mammary tumors tend to be malignant and such disease tends to develop an aggressive behavior pattern. In order to treat the neoplasm, radical surgery followed by adjuvant chemotherapy should be performed. Even so, there is a high frequency within the mortality rate and metastasis, point out to some sort of failure related to therapeutical procedures, specifically in chemotherapy. With that, the present case study had the purpose of exposing the immunoexpression related to proteins that are associated with building drug resistance within the mammary carcinoma found in felines. 46 female cats were used in this study and were surgically operated in both publicly and privately owned hospitals. All tumors were submitted into histopathological analysis, followed by immunohistochemistry in order to successfully detect P-Glycoprotein, the protein which is related to the lungs resistance and metalotioneína (MT). The clinical pathological parameters were correlated through the Log-rank (P<0,05) testing. The presence of distant metastasis, hospital admittance, type of surgery performed and the use of adjuvant chemotherapy was directly associated with survival rates. Both GlycoP and LRP showed, respectively, an intense immune expression of 45,6% and 47,8% of all the cases, meanwhile, the MT presented a discrete immune expression on 45.7% of the cases. However, all proteins were expressed within some degree on the scale. It was also noticed that there is a positive correlation between GlycoP and histological graduation (P=0,049), and MT with molecular subtypes (P=0,023). However, there were no correlations found between the studied proteins and survival. The data collected pointed to the presence of multiple types of resistance-related proteins to antineoplastic breast carcinoma found in felines as well as high correlation with the degree of malignancy found in the neoplasm. Even though those were not correlated with survival, these points may lead to a possible worse prognostic, as well as an eventual low positive response to the adjuvant chemotherapy.

Avaliação da proliferação celular como indicador prognóstico para mastocitomas cutâneos caninos / Evaluation of cellular proliferation as prognostic indicator for canine cutaneous mast cell tumors

Este estudo teve como objetivo avaliar o valor prognóstico de marcadores de proliferação celular em casos de mastocitomas cutâneos caninos. Vinte e três casos foram analisados quanto à expressão imuno-histoquímica de Ki67 e do Antígeno Nuclear de Proliferação Celular (PCNA), sendo subsequentemente acompanhados clinicamente. Observou-se que a expressão de Ki67 mantém relação negativa com a tradicional graduação histopatológica (p= 0,0418; p<0,05 entre os graus I e III), sendo um indicador confiável para o tempo de sobrevida pós-cirúrgica (p=0,0089). A imunoexpressão de PCNA, apesar de estar correlacionada à marcação por Ki67, não apresentou valores estatisticamente significantes na predição da mortalidade em função da doença e do tempo de sobrevida pós-cirúrgico. Os resultados obtidos confirmam que informações sobre a atividade proliferativa tumoral pela detecção imuno-histoquímica de Ki67 podem incrementar a classificação de mastocitomas cutâneos caninos quanto à malignidade.(AU)

This study evaluated the prognostic value of cell proliferation markers for canine cutaneous mast cell tumor cases. Twenty-three cases were analyzed with regard to immuno-histochemical expression of Ki67 and Proliferating Cell Nuclear Antigen (PCNA), and were clinically followed up. Ki67 expression was related to the traditional histopathological grading (p= 0.0418; p<0.05 between grades I and III), and was a reliable indicator of post-surgical survival (p=0.0089). PCNA immunoexpression did not show statistically significant values in the prediction of disease-related mortality and survival, although it is correlated to Ki67 expression. These results confirm that information about tumoral proliferative activity through Ki67 immunohistochemical detection can improve canine cutaneous mast cell tumor grading with regard to malignancy.(AU)