The role of two influx transporters, the organic cation transporter 1 (OCT1) and the sodium/taurocholate co-transporting polypeptide (NTCP), in the hepatic uptake of retrorsine was demonstrated in vitro using cultivated primary rat hepatocytes, hOCT1-expressing Madin–Darby canine kidney cells and/or the human hepatoma cell line HepaRG (Enge et al. This evidence concerns the gene SLC22A1 and hepatocellular carcinoma.