Several factors have been identified, having roles in upregulation of CXCR-4 namely, HIF-1α and VEGF [44]., A study conducted by Wang et al., on breast cancer cells, introduces silibinin as a novel CXCR-4 antagonist, inhibiting chemokine ligand 12-induced migration [45], which supports our findings of decreased levels of CXCR-4 in CT26 cells treated with silibinin. This evidence concerns the gene CXCR4 and breast cancer.