CXCL12 and glioblastoma: In the present study, we evaluated, in a GBM model, the potential effects of one of these novel cyclic peptides, peptide R, which exhibited the best efficacy in inhibiting CXCL12-dependent migration, ERK phosphorylation and wound healing in human melanoma cells [35], and strongly affected migration in osteosarcoma cells cultured in presence of bone-marrow derived mesenchymal stem cells [36].