Multidrug Resistance in Breast Cancer: From In Vitro Models to Clinical Studies

Table 1

The ABC transporters expressed in breast tissue.

Gene	Protein	Tissue	Chemotherapeutic drugs effluxed by transporter	None chemotherapeutic substrates	References
ABCB1	PGP/MDR1	Intestine, liver, kidney, placenta, blood-brain barrier, most tissues	Colchicine, doxorubicin, etoposide, vinblastine, paclitaxel	Neutral and cationic organic compounds, digoxin, saquinavir, many commonly used drugs	[2, 6–9]
ABCC1	MRP1	All tissues	Doxorubicin, daunorubicin, vincristine, etoposide, colchicines, camptothecins, methotrexate	Glutathione and other conjugates, organic anions, leukotriene C4, rhodamine	[2, 6–9]
ABCC4	MRP4	Prostate, testes, ovary, intestine, pancreas, lung, kidney, most tissues	6-mercaptopurine and 6-thioguanine and metabolites, methotrexate	Nucleotide analoges, organic anions,	[6, 7, 10]
ABCC5	MRP5	Most tissues	6-mercaptopurine and 6-thioguanine and metabolites	Nucleotide analogues, cyclic nucleotides, organic anions	[6, 7, 10]
ABCC10	MRP7	Low in all tissues except pancreas		Nucleoside analogues	[11]
ABCC11	MRP8	Low in all tissues except kidney. Spleen, colon, brain	5-fluorouracil		[7, 8]
ABCC12	MRP9	Breast, testes, brain, skeletal, ovary	Not known	Not known	[8, 12]
ABCG2	BCRP	Liver, breast	Mitoxantrone, topotecan, doxorubicin, daunorubicin, irinotecan, imatinib, methotrexate	Prazosin, pheophorbide A, Hoechst 33342, rhodamine	[6, 13]