Thus, should findings suggest that hypoxia driven recruitment of Treg via the CXCL12/CXCR4 axis plays a significant role in basal-like tumours, therapies targeting CXCL12/CXCR4 and HIF pathways, in addition to targeting Treg may be beneficial for this subset of breast cancers that are less likely to respond to conventional therapies. This evidence concerns the gene CXCL12 and breast cancer.