A stable and reliable animal model for hepatocellular carcinoma with portal vein tumor thrombus.

To the Editor:Hepatocellular carcinoma （HCC） is one of the most common cancers worldwide [1,2].Portal vein tumor thrombus （PVTT） has been demonstrated to be a poor prognostic indicator for HCC [3-5].However,effective treatment for the condition is still limited.Understanding the insight into the molecular mechanisms behind PVTT development may help to establish a new therapeutic strategy.Animal models which mimic the development of PVTT in humans are necessary to figure out the molecular mechanisms behind PVTT development.Currently,a wide range of animal models have been established for HCC from different angles,including chemically-induced models like diethylnitrosamine,carbon tetrachloride,thioacetamide,and phenobarbital,geneticallyengineered mouse （GEM） models like Wnt/β-catenin signaling pathway （CTNNB1）,telomerase reverse transcriptase （TERT） activation,aflatoxin B1 and HBV infection,and engrafted models [6-8].