In the past two decades, with the rapid development of molecular and cytogenetics of tumors, there is a deeper understanding of the genetic basis of carcinogenesis and its pathways, in terms of its essence cancer is a genetic disease. Below, we will introduce several methods of prevention of familial cancer. 1.Chemoprevention Cancer chemoprevention is to apply non-cytotoxic pharmacological ingredients to enhance the internal physiological mechanisms of detoxification and immunity to prevent the occurrence and evolution of malignant cells; contrary to chemotherapy for invasive cancer, chemoprevention is to try to block the initiation of cancer process, or to block or reverse the development of precancerous cells during the long latent period of human cancer. 2.Avoiding exposure to carcinogenic substances and enhancing the body’s ability to fight against cancer Cellular carcinogenesis in familial cancer-susceptible individuals still requires a second induced genetic change, so it is essential to avoid exposure to carcinogenic, mutagenic and other cancer-promoting factors, which include giving up bad lifestyles: such as smoking, excessive alcohol consumption; limiting exposure to occupational and other environmental carcinogenic factors; treating chronic infectious diseases such as hepatitis B, pylori 1/3 of cancer deaths are caused by lung cancer, upper respiratory and digestive tract cancer and bladder cancer, which are mainly related to smoking; 1/3 of cancer deaths may be caused by poor dietary habits; and some cancers are related to alcoholic beverages, environmental pollution, chronic inflammation, sunlight, drugs and other factors, so most cancers can be prevented. Inappropriate diet contains carcinogenic and mutagenic ingredients, such as fried, deep-fried, smoked, stained and moldy foods; high-fat foods promote carcinogenesis; on the other hand, foods also contain anti-cancer and anti-mutagenic ingredients can prevent cancer. The American Cancer Society has made the following recommendations on cancer prevention diet: maintain ideal body weight by reducing total calorie intake and increasing physical exercise; at the same time, physical exercise also enhances physical fitness, improves immune function and enhances cancer prevention; diversify balanced and moderate diet; increase the share of diverse vegetables and fruits in food; consume more high-fiber foods such as cereals and beans; reduce total fat intake; limit alcoholic beverages; and limit preserved foods. ; limit alcoholic beverages; limit pickled and smoked and nitrate-containing foods. Enhancing immune function can remove precancerous and cancerous cells that have been genetically altered. Ginseng, Ganoderma lucidum, Gum Fructus, Musk, Toadstool, Zingiber officinale, Asparagus, Chaste Tree, Cordyceps sinensis, Curcuma longa, Fructus Lycii, Monkey’s head mushroom, Rhizoma alba, Bupleurum, Paeonia lactiflora, Rhizoma spinosae and garlic all have different degrees of immune function and anti-tumor effects. 3.Prophylactic surgery Prophylactic surgical resection is an optional means of prevention for many hereditary cancers, but the effect varies considerably among different familial cancer syndromes. For example, it is effective for FAP and type 2 multiple endocrine tumors; prophylactic colectomy for FAP has been listed as a standard clinical procedure; in both of these familial cancer syndromes, there is early onset of symptoms, almost 100% outgrowth rate and the ability to remove organs at risk of cancer development.