CXCR4 and neoplasm: The predominant CXCL12 receptor is the CX chemokine receptor 4 (CXCR4), a protein frequently overexpressed on the surface of human tumour cells of epithelial origin (Scotton et al, 2002; Cunha et al, 2003; Hartmann et al, 2005; Kaifi et al, 2005; Kim et al, 2005; Schimanski et al, 2005).