Mast cells and angiogenesis in canine mammary tumor

The correlation between microvessel density and mast cells density in canine mammary tumors was studied. Sixty-five samples of canine mammary tumors, being 24 benign and 41 malignant, were analyzed. The routine Toluidine Blue staining method was used to assess the mast cells. To evaluate angiogenesis, the immunohistochemical expression of CD31 was assessed. There was no significant difference in either mast cells (P=0.44) or microvessel density (P=0.77) between malignant and benign tumors. A positive correlation was observed between microvessel density and mast cells (r=0.39; P=0.011) in malignant tumors. These results suggest that mast cells may play a role in canine mammary malignant tumors development, promoting angiogenesis, similar to some tumors described in the human species.