Clasificación en subtipos moleculares de tumores de mama de pequeños animales mediante métodos inmunohistoquímicos / Classification in molecular subtypes of breast tumors of small animals through immunohistochemical methods

Antecedentes y Objetivos: Aplicar un panel de anticuerpos (anti -receptor de progesterona, -receptor de estrógenos, -receptor del factor de crecimiento epidérmico humano 2 y -citoqueratina 14) utilizando métodos inmunohistoquímicos en tumores mamarios de pequeños animales para analizar su clasificación en subtipos moleculares y su asociación con la invasión, el grado y el tipo histológico de las neoplasias. Material y Métodos: Muestras de tumores mamarios malignos, 10 de la especie canina y 3 de la felina. Control positivo interno: glándula mamaria no tumoral adyacente a las neoplasias. Resultados: El 23% (3/13) de los tumores fueron del subtipo luminal B, el 23% (3/13) fueron HER2 positivos, el 46% (6/13) fueron basales y el 7,6% (1/13) no se pudieron clasificar porque no expresaron ninguno de los marcadores tumorales analizados. Ningún caso fue del subtipo luminal A. Los 6 tumores basales fueron de grado II o III y presentaban o infiltración de solo el estroma o también invasión vascula Dos tercios de los tumores HER2 positivos presentaban infiltración del estroma y 1/2 tumores resultó ser de grado II. Los tumores luminal B, 2/3 fueron de grado II o III. Todos los controles internos fueron positivos. No se encontraron diferencias significativas en la distribución de los subtipos moleculares entre los diferentes grupos de las variables invasión (p-valor=0,26), ni grado de malignidad (p-valor=0,42). Sí hubo diferencias en el límite de la significación estadística en la distribución de los subtipos moleculares entre los diferentes grupos de la variable tipo histológico (p=0,08). Conclusiones: La aplicación del panel de anticuerpos ha permitido descubrir 4 (luminal B, HER2, basal y sin clasificar) de los 5 subtipos moleculares posibles (AU)

Antecedents and objectives: to apply an antibodies panel (anti-progesterone receptor -estrogen receptor, -human epi-dermal growth factor receptor 2 and cytokeratin 14) using immunohistochemical methods in mammary tumors of small animals to classify them in molecular subtypes and their association with the invasion, grade and histological type of the malignancies. Material and Methods: samples of malignant mammary tumors, 10 from canine species and 3 from feline ones. Internal positive control: non-tumoral mammary gland adjacent to the malignancy. Results: 23% (3/13) of the tumors were of the luminal B subtype, 23% (3/13) were HER2 positive, 46% (6/13) were basal types and 7,6% (1/13) were unclassifiable because they did not express any of the tested tumor markers. None of the cases belonged to the luminal A subtype. The 6 basal tumors were grade II or III and presented only stromal infiltration or vascular invasion as well. Two thirds of the HER2 positive tumors presented stromal infiltration and hal he tumors were grade II. Two thirds of luminal B tumors were grade II or III. All internal controls were positive. There were no signifi-cant differences in the distribution of the molecular subtypes among the different groups of the invasion (p-value=0.26) and malig-nancy grade variables (p-value=0.42). There were differences of borderline statistical significance in the distribution of the molecular subtypes among the different groups of the histological type variable (p-value=0.08). Conclusions: the application of the antibodies panel has allowed to find 4 (luminal B, HER2, basal and unclassified) out of 5 possible molecular subtypes (AU)

Widespread epithelioid angiosarcoma with ventricular wall involvement in a dog.

This paper reports on a canine angiosarcoma, presenting as an "undifferentiated metastasizing tumor". A 14-year-old female Cocker Spaniel was referred to the University of Extremadura Veterinary Clinic for clinical examination after suffering rapid deterioration, with chronic cough, anorexia and cachexia. One week after clinical examination, the dog died of right congestive heart failure and ventricular arrhythmia. Blood counts revealed lymphopenia and platelet depletion. The biochemistry profile was within normal limits, except for a drop in blood urea nitrogen. Cytological evaluation of liver and spleen biopsies revealed clustered anaplastic cells that lacked convincing tissue differentiation. Major findings at necropsy were enlarged spleen and multiple, beige to dark-red nodules ranging from 0.5 to 3 cm in diameter in the heart, lung, liver and spleen. At histological examination, multiple nests of anaplastic epithelioid cells were found in sections from all affected organs. Immunohistochemistry revealed widespread expression of CD31 and Factor VIII-related antigen. The neoplastic cells were negative for CD 18. The diagnosis of epithelioid angiosarcoma, localized in the myocardium, lung, liver and spleen was made. The primary site of the neoplasm could not be determined.