

In a series of elegant experiments, Relf and colleagues isolated angiogenic factors from 64 primary breast tumors and investigated the relationship of these factors to tumor growth and progression. These factors included vascular endothelial growth factor (VEGF), transforming growth factor-β1 (TGF-β1), pleiotrophin, acidic and basic fibroblast growth factor (FGF), and platelet-derived endothelial cell growth factor. Overall, they showed that VEGF is one of the most important mediators of tumor angiogenesis in human breast cancer tissue and that elevated VEGF levels correlated with poor survival. Importantly, Relf et al also showed that, of all the angiogenic factors studied, VEGF was the only factor linked to poor relapse-free survival.16