Prognostic value of tumour vascularity in metastatic melanoma and association of blood vessel density with vascular endothelial growth factor expression

Tumour angiogenesis is essential for tumour growth and metastasis. Several lines of evidence indicate that vascular endothelial growth factor (VEGF) i s a major regulator both of physiological and pathological angiogenesis. In this study we assessed the blood vessel density and VEGF expression of 94 melanoma metastases of 70 patients by immunohistochemistry, utilizing antib odies against human platelet endothelial cell adhesion molecule-1 (PECAM-1, CD31) and VEGF. The number of blood vessels ranged from 4 to 131 vessels/h igh power field (HPF), with a mean value of 32 vessels/HPF (+/- 21) and a m edian of 29 vessels/ HPF. Survival since diagnosis of the primary disease a nd from the start of chemoimmunotherapy, as well as the disease-free surviv al period, was significantly shorter in the high vascularity group of patie nts compared with the low vascularity group (P < 0.05 and P< 0.01, respecti vely). A high overall expression of VEGF in the metastatic melanoma samples was observed. The degree of VEGF expression appeared to have a strong asso ciation with the blood vessel density (P = 0.017). This study demonstrates the clinical role of tumour vascularity in the prognosis of patients with m etastatic melanoma. In addition, the strong association between vascularity and VEGF expression suggests a crucial role for this growth factor in the neovascularization of metastatic melanoma. (C) 1999 Lippincott Williams & W ilkins.