HSPG2 and breast carcinoma: Matrigel, a reconstituted basement membrane extract from the Engelbreth-Holm-Swarm (EHS) sarcoma (Vukicevic et al., 1992), is rich in basement membrane components, including the HSPG perlecan and has been used to study the invasion of breast cancer cells in response to syndecan-1 knockdown (Nikolova et al., 2009; Ibrahim et al., 2013).