Lung cancer is a very common primary malignant tumor of the lung in clinical practice. Most lung cancer patients originate from the bronchial mucosa epithelium, so it is also called bronchial lung cancer. The clinical causes of lung cancer are still not completely clear, but a lot of medical data show that it is related to smoking, stone wool, radon, arsenic, ionizing radiation and other factors, as follows: 1. Intrinsic factors Family genetics, low immune function and endocrine disorders may increase the probability of lung cancer. 2.Smoking People who smoke for a long time in their life may cause abnormal proliferation of epithelial cells in the bronchial mucosa, or phosphoepithelial, squamous epithelial carcinoma or undifferentiated small cell carcinoma. For non-smokers, although they are not very prone to lung cancer, the probability of adenocarcinoma is higher. Atmospheric pollution Atmospheric pollution caused by industrial waste gas, coal and gasoline combustion is known to be one of the factors for the high incidence of lung cancer in urban areas compared to rural areas. Long-term exposure to radioactive substances such as uranium radium and its derivatives carcinogenic hydrocarbons arsenic chromium nickel copper tin iron coal tar asphalt petroleum asbestos mustard gas and other substances can induce lung cancer mainly squamous and undifferentiated small cell carcinoma. 4.Chronic lung diseases Tuberculosis, silicosis, pneumoconiosis and other lung diseases can easily coexist with lung cancer when they occur. In addition, if people have chronic inflammation of lung bronchus or lung fiber scar, it may increase the possibility of squamous epithelial hyperplasia or hyperplasia during the healing process, and some cases may deteriorate into lung cancer. 5.Occupational factors If people are continuously exposed to radioactive substances such as uranium and radium or substances that are easily derivative and carcinogenic, it will easily induce the high incidence of lung cancer. This type of lung cancer is mainly squamous carcinoma and undifferentiated small cell carcinoma.