However, the extrapolation of the in vitro results to accurately predict the toxicity as it would occur in vivo might require the usage of the newly developed human hepatoma cell lines such as HepaRG [64,65,66], which shows stable expression of liver-specific functions over a long period in culture, including high levels of CYP3A4. The gene discussed is CYP3A4; the disease is hepatocellular carcinoma.