E.g., in periportal fibrosis, cytochrome P450-negative hepatocytes are partially replaced by scar tissue (Ghallab et al., 2019a), while in septal fibrosis, fibrotic streaks connect central veins of neighboring lobules hence reduce the number of CYP-positive hepatocytes (Ghallab et al., 2019b). This evidence concerns the gene PPIG and fibrosis.