The parental D12 cells also expressed Abcb1a and Abcb1b in substantial amounts, which can be explained by their hepatoma origin and dexamethasone resistance because hepatocarcinogenesis and dexamethasone treatment have been associated with the activation of Abcb1 genes in rodents [28], [29], [30], [31], [32]. Here, ABCB1 is linked to hepatocellular carcinoma.