Moreover, most liver tumours (25/30) in 6-month-old pten;tp53 cKO fish were found to exhibit histopathological features of high-grade HCC, whereas only 30% of pten KO fish harbouring liver tumours exhibited high-grade HCC features at 6 months of age (Fig. 5b). This evidence concerns the gene PTEN and hepatocellular carcinoma.