MYC and neoplasm: As expected, while normal livers showed a low rate of proliferation, as assessed by the percentage of Ki67 positive cells (n = 5; 2.8 ± 1.1), both models exhibited a robust proliferation in the tumor lesions, with c-Myc/MCL1/pCMV tumors displaying a significantly higher Ki67 index than c-Myc/MCL1/Cre corresponding lesions (53.8 ± 3.5 vs. 67.3 ± 5.8; p < 0.0003; Figure 11A).