Several studies have revealed that the relationship between C-X-C motif chemokine receptor 4 (CXCR4) to stromal cell-derived factor 1 (SDF1), and the high levels of SDF1 expression in bone marrow have a recruiting effect on CXCR4+ hematopoietic stem cells (HSCs) and promote bone metastasis of CXCR4+ tumor cells. This evidence concerns the gene CXCL12 and neoplasm.