CXCR4 and central nervous system cancer: Furthermore, using an in vitro and in vivo U87MG glioma model, we recently showed that CXCR4 inhibition with a novel peptide antagonist not only induces alterations in molecular responses strictly related to the tumor cells but also modulates the reactivity of glioma-associated microglia/macrophages (GAMs), with a polarization into a proinflammatory GAMs phenotype that could be correlated with a potential anti-tumor activity [11].