The expression of CXCR4 in malignant cells is mainly regulated by hypoxia-inducible factors 1 and 2 (HIF1 and HIF2), but it can be induced in breast cancer cells by vascular endothelial growth factor (VEGF), a well-known pro-angiogenic and pro-inflammatory molecule. Here, CXCR4 is linked to breast carcinoma.