CXCR4 and cancer: Statistical gene set overlap evaluation using the comprehensive Molecular Signature data base (MSigDB) on all upregulated genes in the tumour revealed that immune system, cell cycle, CXCR4 pathway, pathways in cancer, GPCR signaling, regulation of actin cytoskeleton, and p53 downstream pathway were among the top 20 significantly activated gene sets (Supplementary Table 4).