The reversal of mitoxantrone resistance in the S1-M1-80 drug-resistant cancer cells by VKNG-2 could also result from an alteration in the subcellular localization of ABCG2 from the cell membrane (i.e., the transporter would not be in the cell membrane, producing a decrease in drug efflux from the cells). The gene discussed is ABCG2; the disease is cancer.