title: Activation of Mammalian target of rapamycin in canine mammary carcinomas: an immunohistochemical study.
abstract: 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.
authors: Instituto de Ciências Biomédicas Abel Salazar, University of Porto (ICBAS-UP), Rua Jorge Viterbo Ferreira n° 228, Porto, Portugal.
authors: L
authors: L
authors: Delgado
authors: Instituto de Ciências Biomédicas Abel Salazar, University of Porto (ICBAS-UP), Rua Jorge Viterbo Ferreira n° 228, Porto, Portugal; Instituto de Patologia e Imunologia Molecular da Universidade do Porto (IPATIMUP), Rua Dr. Roberto Frias, Porto, Portugal.
authors: F
authors: F
authors: Gärtner
authors: Instituto de Ciências Biomédicas Abel Salazar, University of Porto (ICBAS-UP), Rua Jorge Viterbo Ferreira n° 228, Porto, Portugal. Electronic address: pdiaspereira@yahoo.com.br.
authors: P
authors: P
authors: Dias Pereira
mesh_terms: D000818:Animals; D004283:Dog Diseases / Q000378:metabolism / Q000473:pathology*; D004285:Dogs; D005260:Female; D007150:Immunohistochemistry; D015674:Mammary Neoplasms, Animal / Q000378:metabolism / Q000473:pathology*; D058570:TOR Serine-Threonine Kinases / Q000032:analysis / Q000096:biosynthesis*
chemical_list: D058570:TOR Serine-Threonine Kinases
keywords: PI3K/AKT; dog; mammary tumour; phospho-mTOR