Cancer, i.e. malignant tumor, is a disease caused by the loss of normal regulation of body cells and excessive proliferation. “Cancer in the body, sleep prophet”, that is, the initial manifestation of cancer is abnormal sleep, but this is not absolute. Some cancers can cause sleep disorders such as difficulty in falling asleep and waking up at night, and may be accompanied by uncomfortable symptoms such as fever and pain. However, early signs of cancer are not only sleep, but also symptoms such as weakness, loss of appetite, weight loss, abnormal lumps, abnormal bleeding or discharge, and pain may occur. It is recommended to seek medical attention immediately and communicate with doctors for further examination and treatment in time to improve the quality of survival. In addition, regular medical checkups, regular life and healthy diet should be ensured to improve physical quality and help prevent and resist cancer. I. Early symptoms of cancer: 1. Sleep disorders: For example, lung cancer, usually due to cancerous lung tissues, respiratory irritation symptoms and irritating cough occur, and frequent coughing at night can seriously affect sleeping and lead to difficulty in sleeping. As cancer cells will produce endogenous pyrogen during the process of division and lysis, stimulating the thermoregulatory center to cause fever, while the body’s neuromuscular excitement is abnormal during fever, and the body consumes a lot of energy, then metabolic disorder will occur, thus affecting sleep quality, which can be temporarily improved after medication, but will recur. Besides, when the cancer of lung cancer patients involves the pleura, it may also manifest as chest pain and chest tightness, and the phenomenon of waking up from time to time at night due to painful attacks, and the symptom of dyspnea when pleural effusion appears; 2. abnormal lumps: such as breast cancer, the earliest manifestation is painless breast lumps, which are mostly without conscious symptoms and often discovered unintentionally, and a few patients may have different degrees of tenderness or nipple overflow; 3. abnormal Bleeding or discharge: such as cervical cancer, mainly manifested as vaginal bleeding and abnormal vaginal discharge, vaginal bleeding is common after sex or gynecological examination, and the discharge is mostly white or bloody, thin like water with fishy odor; 4. Significant weight loss can occur. Early prevention of cancer: 1. Regular medical checkups: insist on having at least one medical checkup per year, or choose the appropriate interval according to individual age and previous examination results, in order to know the risk of cancer, detect early cancer or precancerous lesions, make early intervention and improve the quality of life; 2. stimulating factors to reduce the damage to the body. At the same time, avoid staying up late and regular rest and relaxation, which is conducive to the stability of endocrine system and cardiovascular system. Avoid contact with radon and other radioactive substances, as well as carcinogenic substances such as formaldehyde and benzopyrene; 3. Healthy diet: eat less high-salt, high-cholesterol and spicy stimulating foods to reduce the burden on the gastrointestinal tract and improve digestion and absorption. Eat more fresh fruits and vegetables and high quality protein to improve the intake of nutrients in the body.