CXCL12 and neoplasm: Interestingly, synergistic effects of CXCL12 and CXCL11 on cell migration were only detectable in tumor cells in which CXCL11-dependent cell migration was sensitive to the p38 inhibitor, SB203580 (A549, A767), and in which CXCL11 and CXCL12 affected cell migration via different signaling pathways.