Stable expression of CDH1-7A mutants in BC cells reduced protein levels of PIN1 and other mitotic proteins including PLK1, CDC20, Cyclin B1 and Geminin with minimal effects on mRNA levels in both RB-proficient and RB-deficient cells, which was rescued by the proteasome inhibitor (Fig. 2g, h). The gene discussed is CDC20; the disease is breast cancer.