Several direct angiogenic inhibitors of endothelial cell functions (angiostatin, endostatin and thrombospondin) and indirect anti-antiangiogenic agents that block the production or activity of pro-angiogenic molecules, such as vascular endothelial growth factor (VEGF) or platelet-derived growth factor (PDGF), have been shown to reduce tumor interstitial pressure [23-25]. This evidence concerns the gene PLG and neoplasm.