Evaluation of angiogenesis in canine seminomas by quantitative immunohistochemistry.

Angiogenesis, which assists in supplying the nutritional and respiratory needs of proliferating cells, is essential for tumour growth. Angiogenic control is complex, involving a network of cytokines, in particular vascular endothelial growth factor (VEGF), a potent endothelial cell mitogen which also stimulates neoplastic cell proliferation. The purpose of this study was to evaluate VEGF expression and microvessel density (number of microvessels per mm(2)), in canine seminomas. VEGF expression and microvessel density were higher in seminomas than in normal testicular tissue; both parameters were higher in diffuse tumours than in intratubular tumours. These data demonstrate an increase in angiogenesis in the more malignant histological types of seminoma and suggest that both VEGF and microvessel density are useful criteria for evaluating the intrinsic malignancy and growth potential of canine testicular tumours.