CXCR4 and gliosarcoma: Munson et al., also found a correlation between the CXCL12–CXCR4 axis and the response to IFF on several cell lines including U87 MG (invasive rat astrocytoma C6; invasive rat astrocytoma RT2; and noninvasive rat gliosarcoma 9L) seeded in gel (0.1% hyaluronan and 0.12% collagen I) [6].