Resistance of RCC to anticancer drugs is considered to be due in part to the activity of the superfamily of drug efflux pumps, which are responsible for ‘classical’ multidrug resistance; p-glycoprotein (also known as MDR1 (multidrug resistance) in human beings) was the first of this superfamily to be identified. The gene discussed is ABCB1; the disease is renal cell adenocarcinoma.