Activation of Mammalian Target of Rapamycin in Canine Mammary Carcinomas: An Immunohistochemical Study

作者：Delgado L; Gaertner E; Pereira P Dias^*

来源：Journal of Comparative Pathology, 2015, 152(2-3): 138-144.

DOI：10.1016/j.jcpa.2014.12.004

• dog
• mammary tumour
• phospho-mTOR
• PI3K/AKT

Mammalian target of rapamycin (mTOR) is a serine threonine kinase involved in cell growth, proliferation and survival. Activation of mTOR has been reported in various tumour types, including human breast cancer; however, the expression of mTOR in canine mammary tumours has not been examined. In the present study, expression of the activated form of mTOR (phospho-mTOR [p-mTOR]) was examined immunohistochemically in five normal canine mammary glands, 45 canine mammary carcinomas and their corresponding metastatic lesions (n=15). Phospho-mTOR was not expressed in normal canine mammary tissue, but cytoplasmic labelling was observed in 78% of canine mammary carcinomas. Two carcinomas had both cytoplasmic and nuclear labelling. No significant relationship was found between p-mTOR cytoplasmic expression and histological type or grading of carcinomas, degree of tubular formation, anisokaryosis, mitotic activity or lymph node metastasis. In all except one case, the expression pattern of p-mTOR in lymph node metastases was similar or decreased when compared with the primary lesion. The findings suggest that p-mTOR is involved in mammary carcinogenesis in dogs. However, p-mTOR cytoplasmic expression does not appear to be a prognostic indicator in canine mammary carcinomas, which may be related to its subcellular location in the neoplastic cells. Canine mammary tumours may provide a model for the development of innovative medical strategies involving mTOR inhibitors in human breast cancer.

• 出版日期2015-4