C. N. Barra

Increased expression of tissue inhibitor of metalloproteinase-1 correlates with improved outcome in canine cutaneous mast cell tumours.

Canine mast cell tumour (MCT) is a biologically heterogeneous disease. The extracellular matrix degradation promoted by matrix metalloproteinases (MMPs) has been studied in an attempt to elucidate the mechanisms involved in the biological behaviour of tumours. The aim of this study was to characterize the expression of MMP-2 and -9 and tissue inhibitors of metalloproteinase (TIMP)-1 and -2 in canine cutaneous MCTs and to evaluate their prognostic values. Immunohistochemical staining for MMP-2, MMP-9, TIMP-2 and TIMP-1 was performed in 46 canine cases of MCTs. TIMP-1 expression showed an independent prognostic value for post-surgical survival and disease-related mortality. Dogs with MCTs showing less than 22.9% mast cell TIMP-1 positivity were more prone to die because of the disease and had a shorter post-surgical survival. This article suggests the involvement of TIMP-1 in MCT progression, by contributing to a good outcome in patients with MCTs.

Apoptotic intrinsic pathway proteins predict survival in canine cutaneous mast cell tumours: BARRAet al.

Mast cell tumours (MCTs) are the most frequent canine round cell neoplasms and show variable biological behaviours with high metastatic and recurrence rates. The disease is treated surgically and wide margins are recommended. Adjuvant chemotherapy and radiotherapy used in this disease cause DNA damage in neoplastic cells, which is aimed to induce apoptotic cell death. Resisting cell death is a hallmark of cancer, which contributes to the development and progression of tumours. The aim of this study was to investigate the expression of the proteins involved in the apoptotic intrinsic pathway and to evaluate their potential use as prognostic markers for canine cutaneous MCTs. Immunohistochemistry for BAX, BCL2, APAF1, Caspase-9, and Caspase-3 was performed in 50 canine cases of MCTs. High BAX expression was associated with higher mortality rate and shorter survival. BCL2 and APAF1 expressions offered additional prognostic information to the histopathological grading systems. The present results indicate that variations in the expression of apoptotic proteins are related to malignancy of cutaneous MCTs in dogs.