In addition, it has also been observed that activated breast cancer-associated stromal myofibroblasts may promote the mammosphere formation and tumourigenicity of breast cancer cells through the release of SDF-1 that in turn stimulates CD44+/CD24−/low BCSCs expressing their cognate receptor CXCR4 and angiogenesis [252]. Here, CXCR4 is linked to breast carcinoma.