Most importantly, the forced expression of Piwil2 led to a clear upregulation of ALDH, MSCA-1, and ABCG2, three common markers of cancer stem-like cells [16], as detected by FACS (Figure 7d), and a significant LD50 increase of cisplatin, as determined by a CCK8 assay (Figure 7e). This evidence concerns the gene ABCG2 and cancer.