All normal cells have a process from new life to death. Controlled by DNA in the cell nucleus, different components of DNA control cell metabolism, proliferation, differentiation and death. If certain DNA (called oncogenes) is altered by endogenous and exogenous factors, the cells gain the ability to multiply and divide continuously without dying, clinically forming tumors. Endogenous factors are divided into genetic, endocrine, nutritional, mental and neurological factors. External factors are divided into physical, chemical, biological and other factors. Internal factors account for 30% of the development of tumor and external factors account for 70%. Factors related to cancer occurrence I. Cancer related to lifestyle Cancer related to smoking Additional factors Oral, upper gastrointestinal tract, respiratory tract Alcohol, malnutrition, chewing tobacco Lung cancer Stone lung, radiation light, airborne infection Pancreatic cancer High-fat diet, heterocyclic amines Kidney cancer, bladder cancer High blood pressure Cervical cancer Human papillomavirus, malnutrition II. . Third, the carcinogenic substances in tobacco and promote carcinogenic substances 1, carcinogens: smoke aromatic hydrocarbons, benzo, dibenzanthracene 2, heterocyclic Both are genotoxic drugs Fourth, promote carcinogens: terpenoids and phenolic compounds, the more the number of smoking, the higher the probability of lung cancer. V. Alcohol is an auxiliary carcinogen Smoking + drinking alcohol can induce oral and esophageal cancers to occur. Alcohol Promotes the production of carcinogens → acetaldehyde → carcinogenic Sixth, smoking and kidney and bladder cancer Smoking metabolizes carcinogens → kidney → bladder → excretion Can induce cancer (more likely to occur when drinking less water)