Lung cancer: people over 40 years old, with a history of smoking or long-term passive smoking. Those who have a history of tuberculosis, especially those who have tuberculosis markings. Those who live in areas with serious air pollution for a long time. Those with a history of exposure to occupational carcinogenic factors, such as: inorganic arsenic compounds, asbestos, radioactive ores, coal smoke, tar, polycyclic aromatic hydrocarbons in petroleum. Breast cancer: middle-aged women between 40 and 60 years old, or women around menopause with family history of tumor. Women who have not had children after marriage, have not been breastfeeding after childbirth or the breastfeeding period is too long or too short, have early menarche or late menopause, have received repeated radiation to the breast for various reasons, have had breast cancer on one side and are obese due to frequent consumption of fat, celibate unmarried women are more prone to breast cancer than married women, and women who work long hours at night have a high risk of breast cancer. Oral cancer: over 40 years old, long-term history of smoking and drinking, poor oral hygiene, long-term stimulation of foreign bodies (caries, poor bite alignment of denture and dentures), poor nutrition and white and red spots of oral mucosa. Esophageal cancer: Older men aged 60 to 70 years old, living in northern areas or rural areas and with a history of smoking, alcohol, family history of tumors and poor dietary habits. Preference for overheated diet, long-term consumption of sauerkraut, pickled and moldy food can contribute to esophageal cancer. Those who have chronic esophagitis with atypical hyperplasia are also at high risk of esophageal cancer. Stomach cancer: people over 40 years old, those with smoking history, family history of stomach cancer, those who are used to salted and smoked foods, and those with history of chronic stomach diseases, such as severe gastric ulcer and atrophic gastritis. Liver cancer: patients with chronic hepatitis, chronic hepatitis B or C, of which hepatitis B is the most important causative factor of liver cancer in China. Young and middle-aged men aged 40 to 50 who live and work in the southeast, those with a history of long-term alcohol consumption, long-term use of moldy food, family history of liver cancer and those suffering from cirrhosis. Colorectal cancer: above 40 years old, with family history of colorectal cancer, postoperative colorectal cancer patients, those who have received radiotherapy to the pelvis, polyps in the colon, stomach cancer, thyroid cancer, breast cancer patients, ulcerative colitis patients, and those who have a long-term high-fat and low-fiber diet. Cervical cancer: middle-aged women aged 44 to 55, women with cervical lesions (long-term chronic cervicitis, precancerous cervical lesions, etc.). Women with family history of tumor, early sexual life, multiple pregnancies and premature births, and women with multiple sexual partners themselves or multiple sexual partners of their spouses. Women who have had human papilloma virus of the reproductive tract, herpes simplex virus, HIV infection or other STDs. Bladder cancer: Men between the ages of 50 and 60 with long-term exposure to aniline, benzidine, and synthetic rubber. Leukemia: Adolescents and those over 40 years of age with a family history of tumors, long-term exposure to radiation, chemical toxins such as benzene, and cytotoxic drugs. Skin cancer: middle-aged and older men between the ages of 50 and 60 who are engaged in open-air work and long-term exposure to ultraviolet light.