ABCB1 and cancer: ABCB1/P‐gp (P‐glycoprotein), multidrug resistance‐associated protein 1 (ABCC1/MRP1) and breast cancer resistance protein (ABCG2/BCRP) are the most studied ABC transporters with well‐established roles in mediating multidrug resistance in cancer cell models.50, 51, 52