CYP3A4 and cancer: Consistent with the results obtained on the siRNA-mediated inhibition of CYP3A4, its pharmacological inhibition with the potent CYP3A4 inhibitor, ketoconazole (KCZ, 1 μM), significantly reversed DOX resistance in cancer spheroid models (n = 5, p < 0.01) (Figure 2D–F).