The dog mastcell tumor as a model to study the relationship between angiogenesis, mast cell density and tumor malignancy

Substantial experimental data suggest that tumour progression is associated with angiogenesis and that increase in microvessel density (MVD) is associated with increase in mast cells density (MCD). Dog mast cell tumour (MCT) is common in dog with an incidence much higher than that found in human and in both species several common biological and clinical characteristics have been demonstrated. To evaluate the role of angiogenesis in progression of this tumour and to correlate MVD and MCD, in this study a series of 78 MCT was investigated. Serial sections obtained from biopsy specimens were processed with toluidine blue staining, specific for MC identification, and by immunohistochemistry using a polyclonal antibody anti factor VIII-related antigen (FVIII-RA), used as an endothelial marker, and MVD and MCD were determined. Results showed that MVD was significantly higher in poorly differentiated (G3) MCTs than in intermediate (G2) and well differentiated (G1) MCTs and that MCD and MVD were significantly correlated in G3, but not in G1 and G2 subgroups. These data indicate that angiogenesis and MCD are significantly correlated in MCTs progression.