In a similar way, we found that ABCG2 was upregulated in the DOX-resistant osteosarcoma lines that showed an increased expression of SOX-2 and OCT-4 (143-B-DX-R and Saos-2-DX-R), but downregulated in the DOX-resistant line which displays a repressed expression of the pluripotency factors (MG-63-DX-R). The gene discussed is POU5F1; the disease is osteosarcoma.