NRP1 and cancer: Furthermore, Neuropilin-1 (NRP-1) and Neuropilin-2 (NRP-2) transmembrane proteoglycans, as well as hyaluronic acid (HA) fragments resulting from the hydrolysis of carbohydrate chains in proteoglycans by HYAL hyaluronidase, also display pro-angiogenic properties in several cancer models (179–182).