One of the primary contributors to chemotherapy resistance is the overexpression of ATP-binding cassette (ABC) transporters, such as P-glycoprotein (P-gp/ABCB1) and BC resistance protein (BCRP/ABCG2), which actively efflux chemotherapeutic agents, reducing intracellular drug accumulation and efficacy [64]. Here, ABCB1 is linked to breast cancer.