Tumors are not contagious, but they are sometimes contagious, mainly related to the bacteria and viruses that are contagious and the biological behavior of cancer in the process of occurrence and development. In fact, stomach cancer is not contagious, but H. pylori can be transmitted from one person to another in daily life, and H. pylori has been proved to be a very important cause of precancerous lesions of gastric adenocarcinoma by various experiments; 2. liver cancer is definitely not contagious, but China is a region with a high incidence of hepatitis B. However, China is a region with a high prevalence of hepatitis B. Many patients have hepatitis B virus carrier, and in the process of hepatitis B virus carrier, it may be infected to other patients, but it is not hepatocellular carcinoma that is transmitted, but the infectious hepatitis B virus. After the transmission of hepatitis B virus, the trilogy of liver cancer occurs, such as hepatitis, cirrhosis, and finally turning to liver cancer, which can be transmitted through a variety of body fluid contact and hematological contact leading to virus transmission. However, it is emphasized that patients are not infected with liver tumor or stomach tumor, but the virus can be transmitted to other people through various ways, which may lead to the development of the disease.