Is cancer contagious? This is a seemingly simple but actually not so simple question. There are two types of cancer transmission: firstly, the cancer cells themselves spread from one patient to another; secondly, the virus or bacteria that cause cancer transmits. So are either of these two types of cancer transmission real? Can cancer cells themselves be contagious? This fear is not new at all. In 18th century Europe, many people feared that cancer was contagious, and Dutch doctors Zacutus Lusitani and Nicholas Tulp followed the popular trend of putting forward the theory that cancer was contagious, which was supported by many of the already panicked masses, although there was little scientific evidence to support it. The pressure of public opinion led directly to the forced relocation of France’s first specialized oncology hospital from the city to a shitty suburb in 1779, where cancer patients were quarantined like infectious patients. The social debate over genetic modification is now like the debate over cancer transmission back then. Theoretically, cancer cells are extremely difficult to transmit for two reasons: 1. Cancer cells are very fragile Unlike what people think, cancer cells are very fragile once they leave their original internal environment. Once cancer cells run out of one person’s body to another person, it is like the Monk himself going to get the scriptures, there are 81 difficulties on the way, and one mistake will ruin one’s life. 2.Strong immune system The human immune system is very strong and good at eliminating all kinds of foreign substances. Foreign cancer cells look strange, even if they have a life to come, they do not have a life to stay. This is true in theory, and it is also true in fact. After more than 300 years of research, excluding the indirect transmission caused by viruses and bacteria mentioned earlier, there are very few cases reported so far in which human cancer cells can be directly transmitted, and none of them has been strictly confirmed. Therefore, the general consensus of the scientific community is that cancer cells are not transmissible from person to person. Bacteria or viruses can cause cancer The second scenario is better understood because we all know that many bacteria and viruses can be transmitted, such as influenza virus, HIV, Mycobacterium tuberculosis, syphilis spirochetes, etc. They can be transmitted from person to person through some channels. Although no bacterial or viral infection can cause cancer 100% of the time, there are at least three major types of infectious bacteria and viruses that are known to contribute to the development of certain types of cancer, so in a way, you can say that these three types of cancer are “contagious”. Hepatitis B virus (HBV) is a familiar term to Chinese people, describing people with chronic hepatitis B or hepatitis B virus carriers. Because the hepatitis B virus causes chronic destruction of liver tissue, hepatitis B virus carriers are 100 times more likely to get liver cancer than non-carriers. Currently, there are no drugs that can completely eliminate the hepatitis B virus, and treatment is mainly based on taking antiviral drugs to control the development of the virus while improving the patient’s own liver function. The hepatitis B virus is mainly transmitted through blood and body fluids, and infants are most at risk, with a 90% chance of infection after exposure to the hepatitis B virus. Fortunately, a good and safe vaccine for hepatitis B virus is now available and should be given to all infants unless there is a specific reason to do so. The hepatitis B virus vaccine has become the first “cancer vaccine” to be approved by the FDA. 2. human papillomavirus (HPV) HPV is responsible for most cervical cancers in women, but both men and women can be infected with this type of virus. In addition to cervical cancer, HPV is also associated with anal cancer, male and female genital cancers, and oropharyngeal cancer. HPV is transmitted primarily through sexual intercourse, and 80% of women become infected with the virus at some point in their lives. Like hepatitis B virus, there is no cure for HPV infection, but there are several good HPV vaccines, also known as “cervical cancer vaccines,” available worldwide and recommended for all girls and boys aged 11 to 16 who have had sex before. 3, Helicobacter pylori (Hp) China is the hardest hit by H. pylori infection. About 70% of the adult population in China carries H. pylori. There are no acute symptoms of H. pylori infection and many people are unaware that they are infected. Long-term H. pylori infection can increase the incidence of gastric cancer by 3 to 12 times. In China, H. pylori infection is clearly familial, and if parents are infected, the chances of children being infected as well are very high. Therefore, if a close family member has stomach cancer and tests positive for H. pylori, it is highly recommended that young people in the family, especially children, be tested for H. pylori and if the infection is confirmed, it should be treated as soon as possible. The above 3 cases are considered to be “cancer transmission”, which is not the same as the traditional sense of transmission, and it is possible to stop these lesions from turning into cancer if the problem is detected and actively prevented. Now, we know that cancer is not contagious among humans. Then we don’t have to be afraid to show our love and care for cancer patients when we come in contact with them. Because those who have cancer are often the ones we love and who love us deeply.