In summary, we propose a model for the regulation of BRD7 by the APC/Ccdh1 and APC/Ccdc20 E3 ligase complex in osteosarcoma (Fig. 7): two activators of the APC/C E3 ligase complex, Cdh1 and Cdc20, bind to BRD7 directly, triggering the degradation of BRD7 and consequently resulting in the loss of BRD7's inhibitory effects on the tumorigenesis of osteosarcoma. The gene discussed is CDH1; the disease is osteosarcoma.