CXCL12 and cancer: The mechanisms underlying the organ-specific nature of bone metastasis are governed by chemoattractants (e.g. CXCL12/SDF1), attachment molecules (e.g. ALCAM, annexin II), and cytokines regulating cell growth and angiogenesis (e.g. IL6 and VEGF) [6],[7]; however, the conditions and factors that regulate the expression or activity of these critical molecules to affect metastatic cancer cell bone colonization, establishment, tumor growth, metastatic progression, and recurrence remain unclear.