ABCB1 and liver cancer: In particular, MDR1 (P-glycoprotein), MRP1 (multidrug resistance-associated protein 1), and MRP3 (multidrug resistance-associated protein 3) were found to be highly overexpressed in biliary cancer [8,9], whereas MDR1, MDR3, MRP3, and MRP5 were linked to a poor prognosis in pancreatic and liver cancers [10,11].