To mimic the different environments in which EC might be embedded in vivo – either subjected to persistent stimulation imposed by the tumor cells or not, EC were investigated both in the presence (Figure 1A) or the absence (Figure 1B) of the angiogenic factors VEGF, FGF- 2, of epidermal growth factor (EGF) and of fibronectin. Here, EGF is linked to neoplasm.