In addition, rat models allow to follow the clonal expansion of initiated cells and their evolution to foci/nodules and then HCC, thanks to a great number of preneoplastic markers, such as gamma-glutamyl transpeptidase (GGT), glutathione S-transferase, placental form (GSTP), cytokeratin-19 (KRT-19), and glucose-6-phosphatase (G6Pase). The gene discussed is KRT19; the disease is hepatocellular carcinoma.