Estradiol induction increases the IC50 of adriamycin against MCF-7 cells and decreases the intracellular accumulation of the drug, accompanied by an increase in the CDC42 protein levels [92], suggesting that CDC42 may be involved in regulating drug transport or receptor degradation, thereby regulating the endocytosis and efflux of chemotherapeutic agents in cancer cells. The gene discussed is CDC42; the disease is cancer.