PTEN and osteosarcoma: In addition to MDR1 expression, we also found significant downregulation of several CtBP1-repressed targets, including CDH1, BAX, BIM, and PTEN. Among these genes, CDH1 is regulated by the CtBP1-ZEB1/2 (zinc finger E-box binding homeobox 1/2) transcriptional complex 26, whereas BAX and BIM expression can be repressed by the CtBP1-p300-FOXO3a (forkhead box O3a) complex in osteosarcoma cells 27.