Lymphatic vascular endothelial hyaluronan receptor-1 (LYVE-1), a selective marker of the lymphatic endothelium, is a surface endocytic receptor for hyaluronan (HA), which is an extracellular glycosaminoglycan involved in cell adhesion and migration. HA is widely expressed on leukocytes, dendritic cells, and tumor cell, and is identified by searching expressed sequence tag (EST) databases for sequences homologous (41%) with the metastasis related CD44 molecules.