Several articles have reported the implication of organic cation transporter (OCT) 1 (encoded by the SLC22A1 gene), OCT3 (SLC22A3) as well as the ATP-binding cassette (ABC) efflux transporters MDR1/P-glycoprotein (ABCB1), multidrug resistance protein (MRP, ABCC2), and breast cancer resistance protein (BCRP, ABCG2) in resistance to drugs which are commonly used in the HCC treatment. The gene discussed is ABCB1; the disease is hepatocellular carcinoma.