Cancer has been called the “plague of the 20th century”. But if you maintain a healthy lifestyle, it may be difficult for this plague to hit you because many cancers are caused by unhealthy lifestyles and lifestyle behaviors. This is by no means sensationalism or claptrap, we all need to prevent cancers brought about by poor lifestyle. There are cancers directly related to heredity and occupation, but they are not many, while those related to human lifestyle or life behaviors account for 80% of cancers. The concept of “lifestyle cancer” was introduced by the medical profession to remind people to pay attention to their lifestyles and abandon bad habits. Why is it necessary to link lifestyle with cancer prevention? Everyone has both proto-oncogenes and anti-cancer genes, which are normally kept in a sealed state. However, if something special happens that makes the proto-oncogene activated or the anti-cancer gene lost, a person will develop cancer. Then how are proto-oncogenes activated and anti-oncogenes lost? It must be related to external factors, which come from people’s lifestyle and life behavior. For example, benzo(a)pyrene has been clearly identified as a carcinogen, how does it enter the human body and cause lung cancer? It is because of smoking and inhaling a large amount of benzopyrene, which is a typical “lifestyle cancer”. Usually, liver cancer, stomach cancer, lung cancer, etc. are different cancers from the organ names. If we look at the causes, cancers can be broadly divided into three categories, namely: biological cancers, including viruses and parasites, such as leukemia, nasopharyngeal cancer, rectal cancer caused by schistosomes, etc.; chemical cancers, such as nitrosamines and benzopyrene can cause esophageal cancer and lung cancer; physical cancers, such as excessive exposure to radiation can cause leukemia, etc. Smoking, alcoholism, staying up late for late night snacking, breathing in the exhaust fumes from cars in the streets with heavy traffic, and even the fumes from frying at home, all have the possibility of causing cancer. The improvement of living standard, the change of lifestyle and the transformation of society have gradually freed human beings from malnutrition and infectious diseases, while a large number of chronic non-communicable diseases are piling up in front of human beings, and cancer is one of them. The unhealthy food, clothing, housing and behavior of human beings have the potential to cause cancer, and this cancer is “lifestyle cancer”. The difference in lifestyles also makes the cancer spectrum different between urban and rural areas. In rural areas, stomach cancer and esophageal cancer have the highest incidence rate, while in big cities, lung cancer and rectal cancer are the most common. The incidence of colorectal cancer among Shanghai citizens has risen from the sixth to the fourth place in the order of cancer incidence, with a net increase of three times, which is proportional to the increase of fat consumption in recent years. 1998 was the first time that the cancer mortality rate in the U.S. declined because Americans became more aware of the relationship between cancer and dietary habits earlier, and through changing dietary habits, quitting smoking and increasing the coverage of hepatitis B vaccine, tumors The decline was achieved through dietary changes, smoking cessation and increased hepatitis B vaccine coverage.