Our study is the first to show that cancer stem-like cells, which expressed the CSC markers CD44 and ABCG2 as well as the stem-cell marker SOX2 [19], exhibited significant sensitivity to TRAIL-induced apoptosis and that α-mangostin functioned as a sensitizer of TRAIL-induced apoptosis by inducing recruitment of DR5 to the cancer cell surface (Fig. 8) [15]. Here, ABCG2 is linked to cancer.