In the TOP-GFPHigh fraction, the invasion abilities (Figure 2a and Supplementary Figure 3), the sphere-forming ability (Figure 2b), the SP percentage (Figure 2c and Supplementary Figure 4) and the expression level of ABCG2 (Figure 2d and Supplementary Figure 5) were much higher than those of the TOP-GFPLow fraction in many cancer cell lines. The gene discussed is ABCG2; the disease is cancer.