CXCR4 and glioma: We next analyzed the downregulated (<3 fold) and the upregulated (>3 fold) gene using STRING (http://string-db.org/) and found four main gene networks consisting of IL-6, BCL2, PTGS2/COX-2 (prostaglandin endoperoxide synthase 2 gene) and CXCR4, that were regulated in glioma cells silenced for RTVP-1 (Fig. 6F).