One of the most significant roles of ABC transporters in toxicology is their contribution to multidrug resistance (MDR). Certain ABC transporters, such as P-glycoprotein (P-gp) and ABCG2, actively efflux chemotherapeutic agents out of cancer cells, thereby reducing drug accumulation and efficacy. This efflux capability is a major obstacle in the treatment of various cancers, as it leads to the development of resistant tumor cells.
