ABCB1 and renal cell carcinoma: Another study suggested that mechanisms of multidrug-resistance to chemotherapy in RCC might also be involved in decreased intake of tyrosine kinase inhibitors (TKIs), including those related with membrane structures, ATP-binding cassette (ABC) drug transporters with P-glycoprotein (P-gp, ABCB1), multidrug resistance associated protein (MRP) 1 (ABCC1), and ABCG2 (breast cancer resistance protein, MXR) [35].