As the two cell lines lacked CXCR7 expression (as described above), the function of which should be taken into account in the effects of CXCL12/CXCR4 on tumor survival, these results suggested that CXCL12 promotes OS cell survival through CXCR4 receptors in the absence of serum. The gene discussed is ACKR3; the disease is neoplasm.