This is also suggested by data in the literature showing that the recruitment and retention of proangiogenic hematopoietic cells to sites of ischaemic tissue damage or to tumours is mediated by the interaction of the SDF-1 with CXCR4 (Ceradini et al, 2004; Aghi et al, 2006; Jin et al, 2006). Here, CXCL12 is linked to neoplasm.