Angiogenesis is crucial in the development of ovarian cancer. VEGF is closely linked to normal ovarian function and is required for the development of the corpus luteum and the maturation of the endometrium. Elevated VEGF expression occurs in all stages of ovarian cancer and is associated with poor prognosis. In fact, VEGF levels appear to be prognostically important. In addition to its role in ovarian-cancer-associated angiogenesis, VEGF overexpression is directly associated with the production of ascitic fluid, a feature probably related to its ability to induce endothelial hyperpermeability. In studies monitoring VEGF after tumor resection, VEGF appears to be a valid tumor marker, following a dramatic decline after surgery, the levels rise at recurrence.