What is the cause of lung cancer?

There are many causes of lung cancer, and it is impossible to say exactly which one causes lung cancer. There may be many reasons * * * the same role or a single role. Details are as follows: 1. Smoking: Whether it is active smoking or secondhand smoke, it is quite conclusive. The incidence of lung cancer in smokers, especially long-term or heavy smokers, is 4- 10 times higher than that in normal people. The incidence of lung cancer in heavy smokers is 10-25 times higher than that in normal people. The earlier you smoke, that is, you start smoking at a very young age. The longer you smoke, the more you smoke, and the greater the possibility of developing lung cancer. Because there are many carcinogens in smoke, including benzo, nicotine and a small amount of radioactive substances released by tobacco, all of which are carcinogenic factors. Some people say that Chairman Mao smokes, and so does Comrade Deng Xiaoping. How can they live to be over 80 years old? This is a case study. Long-term smoking, smoking more, but not getting lung cancer, this is good luck, but a large number of cases show that smoking is the exact factor leading to lung cancer; 2. Air pollution: Indoor air pollution includes second-hand smoke, gas generated by fuel combustion, cooking fume, some gases with carcinogens released by decorating new houses, and marble may also release hydrogen generated by the decay of radioactive materials. What is outdoor environmental pollution? Some heavy industrial cities have high levels of carcinogens in the air, such as benzene, arsenic, chromium and nickel, and some gases produced by the decay of radium and plutonium, all of which are air pollution factors. Therefore, the incidence of lung cancer in China is very high in recent years, which is likely to be related to air pollution; 3. Occupational exposure: Occupational exposure to some carcinogens, including coal tar, arsenic and chromium. The probability of lung cancer is 10-20 times that of normal people; 4. Genetic factors and gene mutation factors: Genetic factors are mainly gene variation, such as the activation of oncogenes and the inactivation of tumor suppressor genes, leading to the occurrence of lung cancer; 5. Other factors: The incidence of lung cancer in these patients has increased, such as having tuberculosis and virus infection. There are also systemic diseases, and organ transplant patients take immunosuppressants for a long time, which leads to low autoimmune ability and easy to cause lung cancer. There are also some patients with long-term mental depression and tension, which will also cause low autonomic immunity and cause lung cancer.