A growing number of studies have confirmed that genetic genes alone cannot cause cancer development, and that environmental factors acting on susceptibility genes present in the body are the key to cancer development. Blocking those clear acquired cancer-causing factors can reduce the incidence of tumors. 1.Improve dietary habits. WHO proposes to prevent cancer through reasonable dietary habits: (1) avoid animal fat (2) increase crude fiber (3) reduce meat (4) increase fresh fruits and vegetables (5) avoid obesity. 2. Minimize exposure to harmful substances. Such as asbestos, aniline dyes, ionic rays and large amount of ultraviolet rays. Smoking is a serious and preventable risk factor in life, and is closely related to the development of lung cancer, head and neck tumors, bladder cancer and pancreatic cancer, so it is advocated that all people should quit smoking. 3, peace of mind, learn to reduce stress. Theoretically speaking, the human body is producing cancer cells all the time, and the immune system can identify and remove them. If you are overly stressed or overworked, the immune function of your body will be reduced, and cancer cells will grow in your body and become tumors to a certain extent. Therefore, it is necessary to have a good state of mind, live a regular life, work with tension and relaxation, and strengthen physical exercise. 4.Knowledge about tumor and timely treatment of precancerous lesions. The emergence of cancer is a process from quantitative to qualitative change. For example, cystic hyperplasia of breast, chronic atrophic gastritis, gastric ulcer, familial polyps, oral leukoplakia, chronic prolonged hepatitis, cervical erosion, long-lasting ulcers in some parts, etc., are not cancerous in themselves, but have a higher chance of evolving into cancer, and if they can be treated effectively in time to interrupt their evolution, the incidence of some tumors can be greatly reduced. 5.Regular medical checkups for early detection of traces of cancer. The manifestation of tumor is not specific in many cases. It is important to pay attention to the abnormal signals of the body and regular medical checkups to help detect cancer at an early stage. For example, if the number of stools increases and diarrhea alternates with constipation, one should be alert to intestinal cancer; waking up early in the morning and sucking blood sputum backwards, that is, blood in sputum spit out from mouth after inhalation of secretions in nasal cavity, is an early manifestation of nasopharyngeal cancer, if these symptoms are found, one should go to hospital for examination and medical treatment in time.