ABCG2 and brain glioma: The expression ratios of ABCG2 were 5.76% on brain glioma cells (Fig. 2A1) and 23.93% on glioma stem cells (Fig. 2A2); those of CXCR4 were 22.80% on brain glioma cells (Fig. 2B1) and 98.60% on glioma stem cells (Fig. 2B2); those of nestin were 39.36% on brain glioma cells (Fig. 2C1) and 97.77% on glioma stem cells (Fig. 2C2).