We did not detect the expression of these three transcription factors in 15-paired clinical biopsies derived from chemoresistant osteosarcoma patients, but our in vitro and in vivo results obtained by knocking down or the blocking CtBP1-FOXM1 complex confirmed a significant improvement in chemoresistance, suggesting a dominant role for the CtBP1-FOXM1 complex at least in the regulation of MDR1 expression. The gene discussed is ABCB1; the disease is osteosarcoma.