Overall, our data suggest that the potential of peptide R as anti-cancer agent, shown by previous in vivo models of lung metastases (B16-CXCR4 and KTM2 murine osteosarcoma cells) and primary growth of human renal cell xenografts [35] can be exploited also in anti-GBM therapy. This evidence concerns the gene CXCR4 and osteosarcoma.