NRAS and hepatocellular carcinoma: Compared to DEN-induced or transgenic HCC model that needs over 6 months to induce HCC, an elegant and simple method was developed for liver-specific transgenesis that combines hepatic overexpression of the human oncogene AKT and NRAS and somatic integration mediated by Sleeping Beauty (SB) transposase system, which allowed generation of HCC transgenic model with reduced time and resource (25).