ABCC3 and breast cancer: Quantitation of the inhibitory concentration 50 (IC50) at 5 days after AZD administration indicated that all the IC50 values are in the low μM range and showed that the different cell lines have a different sensitivity to the drug (i.e., MCF-7 > Y537S > Tam Res) with cells resistant to Tam being the less sensitive to AZD possibly because Tam resistance in BC cells is accompanied by an increased expression of multidrug resistance-associated proteins [33].