The growth of tumors that overexpress the human organic cation transporter-1 (hOCT1, encoded by the SLC22A1 gene) is inhibited by sorafenib, although hOCT1 expression is low in HCC, and hOCT1 expression is negatively correlated with SLC22A1 promoter methylation. Here, SLC22A1 is linked to hepatocellular carcinoma.