ABCG2 and ovarian cancer: MRP1 displayed a higher degree of drug substrate recognition than BCRP, leading to a 2.5-8.8-fold increase in the IC50 values in the MRP1-overexpressing ovarian cancer cell line 2008/MRP1 [50]; co-treatment with the potent MRP1 transport inhibitor MK571 fully restored cellular sensitivity to these drugs, indicating that this drug resistance was solely mediated by MRP1.