Interestingly, both human CCA tissues as well as tumors derived from Notch-overexpressing mice showed significantly increased levels of the cell cycle regulator protein cyclin E. Nonetheless, tumors derived from these models additionally displayed characteristics of HCC or a mixed CCA/HCC phenotype, which together with the high complexity of the model might be seen as an important limitation. Here, CCNE1 is linked to hepatocellular carcinoma.