RESUMEN
HER-2 and HER-3 are transmembrane receptor proteins that are considered to be important but poorly understood biomarkers in canine tumors. In this study, the expression and the localization of HER-2 and HER-3 were evaluated immunohistochemically in canine mammary tumors (n=64; 12 benign, 52 malignant). HER-2 overexpression was identified in 2/12 (16.7%) benign and in 18/51 (35.3%) malignant cases. HER-3 was expressed in a non-nuclear localization in 11/12 (91.7%) benign and 18/52 (34.6%) malignant tumors. In contrast, HER-3 was expressed in the nucleus of neoplastic cells in 0/12 (0%) benign and 22/52 (42.3%) malignant tumors. Nuclear HER-3 expression was higher in neoplastic epithelial cells compared to myoepithelial cells, and positively correlated with high histological grade and lymphatic vessel invasion. These results suggest that nuclear HER-3 expression is significantly associated with tumor progression and metastasis and may serve as a useful prognostic biomarker in canine malignant mammary tumors.
Asunto(s)
Enfermedades de los Perros/genética , Regulación Neoplásica de la Expresión Génica , Neoplasias Mamarias Animales/genética , Receptor ErbB-2/genética , Receptor ErbB-3/genética , Animales , Enfermedades de los Perros/patología , Perros , Femenino , Marcadores Genéticos , Inmunohistoquímica/veterinaria , Linfocitos Infiltrantes de Tumor/patología , Neoplasias Mamarias Animales/patología , Clasificación del Tumor/veterinariaRESUMEN
Angiogenesis plays a crucial role in tumour growth, invasion and metastasis. Mast cells (MCs) release angiogenic factors that promote endothelial proliferation and differentiation. Previous studies have suggested that MCs are involved in tumour angiogenesis due to the release of various pro-angiogenic factors. This study evaluated samples from 40 canine mammary carcinomas and eight healthy non-neoplastic canine mammary glands. Toluidine blue staining was performed to characterize the MCs. Immunohistochemical labelling was performed to detect the number of tryptase-positive MCs and microvessels. MCs accumulated in tumour tissue and were closely associated with blood or lymphatic vessels in the tumour microenvironment. Angiogenesis, as measured by microvessel density, increased in direct proportion to the number of MCs. The correlation coefficient was significantly higher for tryptase-positive MCs than for toluidine blue-stained MCs. These results suggest that MCs are involved in tumour angiogenesis, which in turn influences tumour growth, invasion and metastasis. In particular, MC tryptase may be influential in mediating this function of MCs.