CXCR4 and cancer: As a peptide inhibitor of CXCR4-ligand binding, LFC131 could prevent the effects of SDF-1 continuously up-regulated by sorafenib treatment, and sensitize HCC to sorafenib therapy via suppressing SDF-1/CXCR4-stimulated cancer cell proliferation, which was similar to AMD3100 reported by Chen [23, 33].