ABCB1 and cancer: Its family members, multidrug resistance protein 1 (ABCB1/MDR1/P-gp) and multidrug resistance-associated protein 1 (ABCC1/MRP1), can transport chemotherapeutic drugs with different structures and functions from intracellular to extracellular by using the energy hydrolyzed by ATP, significantly reducing intracellular drug concentration and playing an important role in the development of cancer chemoresistance [82, 83].