Further, studies in mouse models of cancer showed that VEGF-C produced by tumor cells promoted expression of COX-2 (an enzyme involved in the biosynthesis of prostaglandins) in the endothelial cells of collecting lymphatic vessels, whereas VEGF-D did not, indicating that these growth factors may exhibit distinct regulatory mechanisms for promoting metastasis via the lymphatic vasculature (5). Here, VEGFD is linked to cancer.