In addition, the CD49f+/CD44+/CD24− single cell derived clone S2B11 had a significantly enhanced mammosphere formation and cell migration ability compared to S1F8, the most aggressive clone derived from the CD49f+/CD24− stem cell population (Figures 2C and 2D), suggesting that the clone S2B11 derived from CD49f+/CD44+/CD24− single cell represent the aggressive phenotype of cancer stem cells within the CD44+/CD24− subpopulation. This evidence concerns the gene CD44 and cancer.