ABCG2 and cervical cancer: In contrast, Piwil2 knockdown led to the significant downregulation of c-Myc, Nanog, Oct4, Sox2, and Klf4 (Figure 7c) and slightly decreased the percentage of ALDH-, MSCA-1-, and ABCG2-positive cells, thus rendering cells more sensitive to cisplatin, as compared with cervical cancer cells transfected with the control vectors (Figure 7c, 7d, and 7e).