SLC22A1 and hepatocellular carcinoma: This mechanism, OCT1 (Organic Cation Transporter 1), encoded by the SLC22A1 gene, is responsible for sorafenib uptake, and its down-regulation is associated with shorter OS in HCC patients treated with this specific drug [37]; P-glycoprotein, also known as MDR-1 (multidrug resistance protein 1) or ABCB1 (ATP-binding cassette sub-family B member 1), causes expulsion of sorafenib from the intracellular space [38].