CXCR4 and breast cancer: A preclinical study demonstrated that GMI-1271, a highly specific glycomimetic E-selectin binding inhibitor, blocked E-selectin on the lumen of specialized vascular beds in the bone marrow, preventing vessel adhesion and subsequent passage of circulating breast cancer cells into the tissue, and that AMD3100 (a CXCR4 inhibitor) forced dormant breast cancer cells, inhabiting these same perivascular niches, into the bloodstream [232].