CXCL12 and breast cancer: In breast cancer, stromal fibroblasts respond to pre-tumoral cells by undergoing epigenetic changes, which lead to altered molecular composition of the extracellular matrix (ECM) [8,9], with increased deposition of collagens, fibronectin and tenascin [10], and increase in inflammatory cytokines and growth factors, such as VEGF and CXCL-12, which promote vascular development and cancer cell proliferation and invasiveness [11-15].