It has been clarified that there is a highly significant correlation between Gd-EOB-DTPA uptake and OATP1B3 expression in HCC cells and/or normal hepatocytes, and also between the grade of OATP1B3 expression and the enhancement ratio (signal intensity) during the hepatobiliary phase of Gd-EOB-DTPA MRI [19,20]. The gene discussed is SLCO1B3; the disease is hepatocellular carcinoma.