CASP3 and hepatocellular carcinoma: The HCC formation was analyzed by histological, immunochemical and molecular biology methods, and the immunochemical data indicated an increase in proliferating cell nuclear antigen (PCNA) and active caspase 3 expression in the edn1 transgenic fish at 7 to 11 months of age, which correlates with the age of hyperplasia and HCC formation.