High Expression of Extracellular Matrix Metalloproteinase (MMP-9) Associated with Canine Mammary Tumors
World Small Animal Veterinary Association World Congress Proceedings, 2014
T. Raposo-Ferreira1; R. Salvador1; E. Terra1; J. Ferreira2; M. Carvalho3; G. Varallo1; S. Rogatto4; R. Laufer-Amorim5
1Department of Clinical and Veterinary Surgery, São Paulo State University (UNESP), Jaboticabal, Brazil; 2Department of Morphology, 3Department of Genetics, 4Department of Urology, 5Department of Clinical Veterinary, São Paulo State University (UNESP), Botucatu, Brazil


Mammary tumors are the most prevalent tumor in bitches and the incidence of malignant mammary tumors in Brazil exceeds 70%. Metastasis development is one of the main causes of tumor-related death. Matrix metalloproteinases are capable of degrading type IV collagen, facilitating metastatic progression.


Evaluate MMP-9 gene expression in benign and malignant canine mammary tumors.


Fresh normal mammary glands (n = 5), benign mammary tumors (n = 6), non-metastatic carcinoma (n = 18) and metastatic mammary carcinoma samples (n = 11) were evaluated for MMP-9 gene expression by RT-qPCR. The metastases of mammary carcinomas were located in regional lymph nodes, lung, liver, spleen and adrenal, but only primary tumors were evaluated. The patients of this study had a 2-year followup.


High expression of MMP-9 was correlated with benign mammary tumors (p = 0,0087), non-metastatic mammary carcinomas (p = 0,0081) and metastatic mammary carcinomas (p = 0,0022) when compared to normal mammary glands. No statistical difference among benign tumor, non-metastatic and metastatic mammary carcinomas was observed (p > 0,05). Women studies have shown that MMP-9 gene expression is strongly associated with tumor metastasis and, in bitches, an increase of MMP-9 protein expression was found in malignant tumors.


Although benign tumors and non-metastatic carcinomas have shown increased expression of MMP-9 mRNA, higher levels were found in metastatic mammary carcinomas that can be an initial event in tumors to facilitate metastatic progress.

Grant 2013/03940-4, São Paulo Research Foundation (FAPESP)


Speaker Information
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T. Raposo-Ferreira
Department of Clinical and Veterinary Surgery
São Paulo State University (UNESP)
Jaboticabal, Brazil

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