CXCR4 and glioblastoma: <b>Methods</b>: The ability of different combinations of cytokines CXCL12, IL-1β, IL-6, and EGF to stimulate the migration of the GBM cell lines U87, U87 CXCR4+, F98, and U118 was assessed with a two-layer Matrigel device that simulates the extracellular environment in brain.