In clinical work, many patients ask why liver cancer occurs and what are the causes of liver cancer, and many scientists have conducted long-term, extensive and painstaking research on this issue. The causes of hepatocellular carcinoma are as follows: 1. Hepatitis B and C cirrhosis: Most patients with hepatocellular carcinoma are accompanied by cirrhosis caused by hepatitis B and C virus infection, and some experts regard liver sclerosis and liver hyperplasia nodules as precancerous lesions. There is a trilogy of hepatitis B: hepatitis B – cirrhosis – liver cancer; whether hepatitis B virus or hepatitis C virus is not cleared in the acute stage to form chronic infection, it will repeatedly and progressively cause liver cell inflammation and necrosis, followed by liver cell proliferation and fibrous tissue proliferation to repair the damage. “mutation to form cancer cells. The integration of hepatitis B virus with the genes in the nucleus of hepatocytes is also harmful, and the accumulation of unfavorable factors such as decreased immunity of cirrhotic patients who cannot destroy those “bad molecules” in time also gives cancer cells a chance to form cancer nodules or lumps. 2, aflatoxin: this is a kind of food contamination, improper preservation of mold produced by toxins, very toxic. Both animal experiments and a large number of studies on dietary components of the population have confirmed that it has a great relationship with liver cancer, and feeding aflatoxin to animals can induce and produce animal models of liver cancer. 3, benzo(a)pyrene is also a harmful pathogenic factor: oil smoke, smoke, baking, fried food contains more or less of this substance. 4, cyanobacteria in ditch and pond water: ditch and pond water contains a harmful algae called cyanobacteria, which is a substance proven to have a clear carcinogenic effect. Jiangnan Water District has effectively reduced the incidence of liver cancer by changing the drinking pattern from direct drinking of ditch and pond water to tap water. 5, other chronic liver diseases: such as alcoholic liver disease, autoimmune liver disease and even fatty liver cirrhosis may cause liver cancer, and any disease that repeatedly causes liver damage, hepatocytes and liver fibrosis to proliferate repeatedly may lead to liver cell mutation over time. Whether liver cancer occurs or not is also related to many other factors, such as family history of cancer, human immunity, living environment and lifestyle habits, including personality and mentality. Understanding the factors that induce and promote liver cancer can help us avoid, prevent and monitor the occurrence of liver cancer and detect the lesions at an early stage. For example, standardized antiviral and anti-liver fibrosis treatment, and delaying and stopping the occurrence of cirrhosis can effectively reduce and prevent the occurrence of liver cancer, which has been recognized by the medical profession.