Why do people get cancer?

Secret: Why do people get cancer? Every year, 7 million people in the world die of cancer, and 6.5438+0 million people in China lose their lives. Scientists have made great efforts to overcome this incurable disease. But until now, we still have not found a way to conquer cancer. What is cancer? Where does it come from and how does it harm people? Sun Yan, academician of China Academy of Engineering and consultant of the Cancer Department of the World Health Organization, answered the reporter's questions. Question 1: How does cancer bring down the human body? First of all, Academician Sun Yan pointed out that cancer is also called malignant tumor, and there are relatively benign tumors. Tumor refers to a local mass formed by abnormal proliferation of cells in local tissues under the action of various tumorigenic factors. Benign tumors are easy to clean up, generally do not metastasize or recur, and only have squeezing and blocking effects on organs and tissues. However, malignant tumors can also destroy the structure and function of tissues and organs, causing necrosis, bleeding and infection, and patients may eventually die of organ failure. Academician Sun told reporters that the basic unit of cancer lesions is cancer cells. After aging and death, human cells will be replaced by new cells to maintain their functions. It can be seen that most cells in the human body can proliferate, but this proliferation is limited, and the proliferation of cancer cells is endless, which makes the nutrients in the patient's body be consumed in large quantities. At the same time, cancer cells can also release a variety of toxins, causing a series of symptoms. If not found and treated in time, it can also be transferred to various parts of the body for growth and reproduction, which will eventually lead to emaciation, weakness, anemia, loss of appetite, fever and organ dysfunction. Cancer can occur in almost every part of the human body. Originally, the biological machine of human body runs seamlessly, but cancer has changed this situation, and its task is to destroy it. If it continues, it will drag down the human body. However, unlike viruses, tumors are not intruders in vitro, and their components are the same as normal tissues, so the body cannot recognize them. Question 2: Where do cancer cells come from? Academician Sun made an analogy to the reporter: the human body is actually a community of cells. Every cell follows rules, knows when to grow and divide, and knows how to combine with other cells to form tissues and organs. The "drawings" of different tissues are genes. Many people say that there are cancer cells in the human body, but they have not developed. Medically speaking, if cancer cells can be detected, this person can be diagnosed with cancer. Therefore, this statement is incorrect. Now medical scientists believe that everyone has proto-oncogenes in his body, and definitely not everyone has cancer cells in his body. Proto-oncogenes are responsible for cell division and proliferation needed for human growth. In order to "control" it, there are tumor suppressor genes in the human body. At ordinary times, proto-oncogenes and tumor suppressor genes maintain a balance, but under the action of carcinogenic factors, the power of proto-oncogenes will increase and tumor suppressor genes will weaken. Therefore, carcinogenic factors are the "key" to start the growth of cancer cells, mainly including mental factors, genetic factors, lifestyle, certain chemicals and so on. Start the "cancer program" with the "key" together; The more "keys", the greater the chance of starting. We can't crack all the keys yet, so we can't conquer cancer yet. Academician Sun pointed out that tumor cells are differentiated from "defective" normal cells, and it will take many years to grow into tumors. The "renegade" cells deviate from the track, and the proliferation rate is set by themselves. Only when it accumulates to more than 654.38+0 billion will we notice them. The proliferation rate of cancer cells is calculated by doubling time, 1 change 2, 2 change 4, and so on. Such as gastric cancer, intestinal cancer, liver cancer, pancreatic cancer and esophageal cancer, the average doubling time is 33 days; The doubling time of breast cancer is more than 40 days. Because cancer cells are multiplying, the more advanced cancer is, the faster it develops. Question 3: How does cancer metastasize? "Cancer cells are very greedy." Academician Sun said that it will run to any place it may reach, and there are three main paths: lymphatic metastasis is generally the earliest, so lymph node dissection is needed when tumor resection is carried out; Radiotherapy not only irradiated the primary tumor focus, but also irradiated the surrounding lymph nodes. Lymphatic system is all over the body, which is the ideal first choice for cancer cell metastasis. Lymphatic metastasis often goes from near to far. For example, breast cancer first metastasized to the ipsilateral axillary lymph nodes, and then to the clavicle, axillary lymph nodes, and even the contralateral axillary lymph nodes. Cancer cells directly invade blood vessels or enter blood vessels through lymphatic vessels, and will reach other parts such as lung, brain, liver and bone with blood flow, which is blood metastasis. Gastrointestinal cancer often metastasizes to liver and lung, breast cancer, renal cancer and osteosarcoma often metastasizes to lung, lung cancer easily metastasizes to brain, and prostate cancer easily metastasizes to bone. Chemotherapy is to prevent cancer cells from transferring through blood, and to eliminate cancer cells "along the way" with drugs. There is also a relatively small transfer, that is, planting transfer. Cancer cells fall off from the tumor surface and fall into the chest cavity, abdominal cavity and cerebrospinal fluid, which will "take root and sprout". It usually occurs in the lower part of these cavities, such as costal diaphragm angle, rectal bladder fossa, skull base and so on. Finally, Academician Sun told reporters that people always like to say that something causes cancer. In fact, we can't say that we won't get cancer as long as we don't eat anything, or that we will get cancer if we touch anything. At present, no factor has been found to be an inevitable factor in inducing cancer. The most important thing to overcome cancer is early detection, and most early cancers can be cured. To this end, first, regular physical examination, and second, if you feel uncomfortable, you should see a doctor. Some symptoms may be related to cancer, so don't feel pain before seeing a doctor. Four things to prevent cancer. First, don't smoke or quit smoking. Half of smokers will die of smoking-related diseases, many of which are cancer. In the United States, 90% of lung cancer is directly caused by smoking, and the other 3% is caused by inhaling secondhand smoke. Ferry said, "I don't know why people spend three to five dollars a day to help them live for eight to 12 years." Second, pay attention to what you eat. The American Cancer Society suggests that people should eat at least five different vegetables and fruits every day, which is an effective way to help fight cancer. Nutrition and Cancer magazine also announced that people who seldom eat fruits and vegetables are twice as likely to get cancer as those who eat more fruits and vegetables. The American Cancer Society also suggests: choose whole wheat flour instead of refined wheat flour, limit the intake of red meat, especially eat less processed high-fat meat, limit alcoholic beverages, and so on. Third, do more exercise. Moderate exercise is a kind of exercise recommended by scientists. According to research, walking for an hour every day can reduce the possibility of colon cancer by 46%. The American Cancer Society advises people to take at least 60 minutes of moderate or light exercise every day and exercise more than five times a week. Ferry added that obesity also increases the possibility of cancer. Fourth, understand the family history. Family history is the biggest cause of fatal cancer, and heredity may lead to carcinogenic factors in genes. If immediate family members (parents, siblings, children) have cancer, then you may need to have regular checkups when you are young. But in any case, people should not be afraid, but should take a positive attitude to prevent cancer. Food for preventing cancer 1) Milk and yogurt Milk contains calcium and vitamin D, which can combine with carcinogens in the intestine to eliminate their harmful effects. Yogurt can inhibit the growth of tumor cells. 2) Honey and bee milk honey can promote metabolism, enhance the body's resistance, improve hematopoietic function and tissue repair. In recent years, it has been found that bee milk contains special bee lactic acid, which is effective in preventing and treating malignant tumors. 3) Tea contains catechins, which can remove radioactive substances from the body. Regular drinking tea for radiotherapy patients is beneficial to their recovery. Tea can also prevent dental caries. 4) The function of pollen food is to improve intelligence, promote development, enrich blood, increase endurance, delay aging, have hormone-like effects and enhance disease resistance. 5) Vegetables Fresh vegetables, such as carrots, radishes, preserved fruits, eggplants and cabbages, contain interferon inducers, which can stimulate cells to produce interferon. This substance can enhance the patient's resistance to disease and cancer. But it is easy to be damaged by heat, so the above. Food should be eaten raw. Many studies have confirmed that garlic has anti-cancer ability, and the fat-soluble volatile oil in garlic can activate macrophages and improve the anti-cancer ability of the body. It also contains a sulfur-containing compound, which can also kill tumor cells. Onion can also resist cancer, probably because it contains glutathione and multivitamins. It can be used for preventing lymphoma, bladder cancer, lung cancer and skin cancer. 6) Seafood can be used as dietotherapy food for patients with malignant tumor. The effective components of seaweed are mainly polysaccharide and sodium alginate. Sodium alginate can combine with radioactive strontium and be excreted. Eating kelp, seaweed and other foods often is good for your health. Shark cartilage can inhibit tumor growth, and shark fin has the ability to inhibit tumor infiltration around. Fish is rich in inorganic salts such as selenium, zinc, calcium and iodine, which is also good for anti-cancer. 7) Fungal foods contain polysaccharides and interferon inducers, which can inhibit tumors. Mushrooms have certain curative effects on gastric cancer, esophageal cancer, lung cancer and cervical cancer. Flammulina velutipes also has the same effect and has an inhibitory effect on tumors. Hericium erinaceus has curative effect on gastric cancer, which can prolong the survival time of patients and improve immunity. Tremella has an inhibitory effect on cancer. In recent years, it has been found that 90% of B- pachyman in Poria cocos can enhance immune function and has anticancer effect. 8) Fruit almond can improve immune function and inhibit cell canceration. It can relieve symptoms such as dry mouth, but it is not suitable for patients with inflammation, ulcer and nosebleeds. Mume also has anticancer effect, and jujube can inhibit the growth of tumor cells. Fig extract can be used for treating gastric cancer, laryngeal cancer, cervical cancer, bladder cancer, etc. Apples contain a lot of pectin, which can be combined with radioactive elements to promote their discharge. Papaya can prevent the spread and development of cancer. 9) Steroids extracted from other sweet potatoes can inhibit the development of breast cancer. Corn flour can inhibit tumor growth and reduce the side effects of anticancer drugs. Polysaccharide and coix lachryma-jobi fat in coix lachryma-jobi seed can enhance immune function and inhibit tumor cells. Prevention of cancer, how to eat (1) Food diversification: A wide diet can not only meet all kinds of nutrients needed by the body, but also inhibit harmful carcinogens. (2) Drinking must be moderate: excessive drinking is harmful to health, and oral cancer, throat cancer, esophageal cancer and liver cancer are all related to excessive drinking. People who drink too much and smoke at the same time have a greater risk of cancer. (3) Avoid excessive cholesterol intake: A low-fat diet can reduce the risk of breast cancer, prostate cancer, colon cancer and rectal cancer. (4) Eat foods containing enough starch and cellulose: eat more fruits, vegetables, dried beans, whole grains, beans and their products. Increase the intake of starch and cellulose, which can reduce colon cancer and rectal cancer. (5) Keep the nutritional balance and maintain the ideal weight. Avoid eating too much sugar. Cancer prevention by diet 14 method Cancer is the biggest enemy of human health at present. About 6 million people worldwide die of cancer every year, of which about130,000 people in China die of cancer. However, cancer can be controlled. The World Cancer Research Foundation has devoted itself to the basic, clinical and anti-cancer research of cancer for many years, summed up the research results in the field of cancer in various countries in the world, and put forward 14 suggestions on preventing cancer from diet and health with broad scientific basis. The excerpts are as follows: Recommendation 1: Reasonable diet. Plant foods, such as vegetables, fruits, cereals and beans, should account for more than 2/3 in the daily diet. Recommendation 2: Control your weight and avoid being too light or too heavy. Weight gain in adulthood should not exceed 5 kg. Measured by body mass index (BMI) formula. (See formula) Weight (kg), body mass index = ———————————————— Height (m) × height (m), and the body mass index is less than 20, so it belongs to thinness; Body mass index is 20 ~ 25, which is the ideal weight; Body mass index 25 ~ 30, slightly overweight; Body mass index greater than 30, seriously overweight. Recommendation 3: Stick to physical exercise. If there is little or only light activity at work, you should have a brisk walk or similar exercise of about 1 hour every day. At least 1 hour strenuous activity of sweating should be carried out every week. Recommendation 4: Eat more fruits and vegetables. You should eat 400 ~ 800 grams of fruits and vegetables every day. Green leafy vegetables, carrots, potatoes and citrus fruits have the strongest anti-cancer effects. Eat more than five kinds of fruits and vegetables every day, and stick to it all the year round to have a lasting anti-cancer effect. Recommendation 5: Eat 600 ~ 800g of various cereals, beans and plant roots every day, and the less processed food, the better. Eat less refined sugar. Recommendation 6: Do not advocate drinking. Even if you want to drink, men should not drink more than two cups a day, and women should not drink more than one cup a day. Recommendation 7: Eat no more than 90g of red meat (i.e. cattle, sheep and pork) every day. It's better to eat fish and poultry than red meat. Recommendation 8: Eat less high-fat food, especially animal fat. Select the appropriate vegetable oil and control the dosage. Recommendation 9: Eat less salt and less pickled food. The daily consumption of salt should be less than 6 grams (about one teaspoon). Suggestion 10: Don't eat food that has been stored at room temperature for too long and may be contaminated by mycotoxin. Suggestion 1 1: Preserve perishable food by cold storage or other suitable methods. Recommendation 12: The levels of additives, pollutants and residues in food are lower than the national limit, which is safe, but improper use or misuse may affect health. Suggestion 13: Don't eat burnt food, and don't eat fish and meat or bacon barbecued directly on the fire. Bacon can only be eaten occasionally. Recommendation 14: People who basically follow the above recommendations generally do not need to take nutritional supplements, which may not help to reduce the risk of cancer.