ABCG2 and cancer: Finally, among the upregulated DEGs, we observed in the GR cells a strong induction of several cancer stem cell (CSC) markers previously identified in NSCLC [9]: a cluster of differentiation antigens such as CD117 and CD133, cell membrane transporters such as ABCB1 and ABCG2, Frizzled family receptor (FZD) members, and ALDH1 isoforms (Figure 4).