Among these substrates, we first focused on SDF-1α, since SDF-1α is highly expressed by stromal cells in lung tissues and promotes lung metastases of CXCR4-expressing melanoma cells and breast carcinoma cells by stimulation of tumour cell adhesion to endothelial cells and tumour cell growth under stress (Muller et al, 2001; Murakami et al, 2002). Here, CXCL12 is linked to breast carcinoma.