The first report providing evidence for the presence of breast CSCs (BCSCs) observed that CD44+/CD24low/ESA+/lineage− (named CD44+/CD24−/lo henceforth) cells (Table 1), isolated from human breast tumors by fluorescence activated cell sorting (FACS), were enriched for CSCs that were adequate to seed tumors in immune-deficient mice [14]. Here, CD44 is linked to breast neoplasm.