Canine Transmissible Venereal Tumour: Asessment of Mast Cell Numbers as Indicators of the Growth Phase
Department of Paraclinical Veterinary Studies, University of Zimbabwe, Harare, Zimbabwe.Veterinary Research Communications (Impact Factor: 1.24). 09/2006; 30(6):613-21. DOI: 10.1007/s11259-006-3309-1
Mast cells are immune cells that are involved mainly in type 1 hypersensitivity reactions, and they have been implicated in tumour angiogenesis. In this study we assessed the presence of mast cell numbers and microvessel density during the progression and regression stages of natural spontaneous canine transmissible venereal tumours (CTVT). Mast cells were demonstrated by histochemical staining with toluidine blue, alcian blue and safranin O. Microvessel counts were demonstrated by immunohistochemical labelling with an antibody against the endothelial cell marker factor VIII. Mitotic cells, apoptotic cells and tumour infiltrating lymphocytes were counted from haematoxylin-eosin-stained sections. Tumour fibrosis was evaluated on Masson's trichome-stained sections. The results showed that progressing tumours had significantly higher mast cell counts and microvessel counts at the invasive edges of the tumours than did regressing tumours. In both the progressing and regressing tumours, microvessel counts were significantly positively correlated with mast cell counts. Regressing tumours had significantly higher mast cell counts of the whole tumour than progressing tumours. The results also showed that progressing tumours had significantly higher mitotic rate than regressing tumours, and fibrosis and apoptosis were significantly higher in regressing tumours than progressing tumours. There were no significant differences between the biochemical and haematological values of dogs with progressing and regressing tumours. These results suggests that mast cells play a role in CTVT progression probably by promoting vascularization at the invasion front during the progression phase, and that mast cell count could be used as one of the histological factors to indicate growth stage of CTVT.
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ABSTRACT: Cancer is one of the most common causes of death in dogs. The availability of multiple treatment modalities and novel therapeutic targets make the correct diagnosis, prognostic stratification, and the identification of treatment effect predictive factors an issue of major debate in cancer management. Selection of high and low risk patients and the type of systemic or local treatment is important in cancer management. The search for better prognostic markers and predictive factors is now focused on the molecular mechanisms which underlie tumour behaviour, such as altered cell cycle progression, proliferation, apoptosis, and angiogenesis. The ultimate goal is to identify reliable markers that can accurately diagnose and stage a tumour and predict tumour's clinical behaviour, prognosis and response to therapy. In this review, the current state of prognostication in canine tumours and promising new molecular markers are discussed. The markers are allocated to four groups according to their function: (i) proliferation markers, (ii) apoptosis, (iii) extracellular matrix and cell adhesion molecules, (iv) angiogenesis and (v) cell cycle regulators. Clinicopathological factors and histopathological grading remain the most practical parameters in decision-making. Although experimental research has shown that molecular markers have a good potential to be used as diagnostic, prognostic or predictive markers in canine tumours, insufficient evidence exists on their efficacy for routine use in veterinary oncology.The Veterinary quarterly 07/2005; 27(2):52-64. DOI:10.1080/01652176.2005.9695186 · 0.72 Impact Factor
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ABSTRACT: The biological significance of mast cells and angiogenesis in canine melanomas is unclear. Eighty canine melanomas (56 malignant and 24 benign), investigated to determine the relationship between mast cell count (MCC), microvessel density (MVD) and clinicopathology, revealed significantly higher MCC and MVD counts in malignant melanomas. Evaluation of the prognostic significance of MCC and MVD in malignant melanomas showed a significant correlation between MCC and MVD both within and at the edges of the tumour. Multivariate analysis indicated that MCC and MVD were independent predictors of survival but the former was a significantly better prognostic marker. Greater numbers of mast cells and microvessels were found in malignant melanomas of poor prognosis. The findings demonstrate a prognostic significance of MCC and MVD in canine melanocytic tumours.Veterinary Dermatology 05/2006; 17(2):141-6. DOI:10.1111/j.1365-3164.2006.00505.x · 1.73 Impact Factor
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ABSTRACT: ntroduction and aim - Canine transmissible venereal tumour (CTVT) is a neoplasm with unique features. Despite occasio- nal spontaneous regression of the tumour, veterinarians often have to treat it by chemotherapy. This study aimed to evaluate a new bi-weekly vincristine treatment in comparison to the traditional weekly protocol for CTVT. Materials and methods - 30 dogs with CTVT were divided into two groups: 10 dogs in the control group A and 20 dogs in the experimental group B, treated with weekly and bi-weekly 0.025 mg/kg iv of vincristine sulphate respectively. All animals we- re monitored during treatment by gross evaluation of the tumour, cytology and haematic samples (CBC and hepatic profile). Therapy was suspended when neoplastic cells were no longer found in smears. Results and discussions - In group B, complete remission was obtained for all the dogs after 2.2 ± 0.3 administrations of vincristine. Regarding group A remission was obtained in 9 dogs after 3.6 ± 0.7 administrations. Only mild side effects were observed with no significant differences between groups. A bi-weekly vincristine regimen may be an alternative or elective treat- ment for CTVT, being successfully applied to animals in which weekly therapy is impractical. A bi-weekly schedule is advanta- geous for both owners and animals.Rivista ufficiale della SCIVAC 07/2008; 22(4):13-18. · 0.10 Impact Factor
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