Although there is a certain age range for the onset of tumor, it is not absolute, the youngest can be more than 10 years old and the oldest can be 80-90 years old. 2. Early symptoms are not typical, so we should be alert. If the symptoms cannot be explained well, we should pay attention to gastroscopy and enteroscopy to exclude the possibility of tumor. 3.The incidence is increasing year by year → (hepatitis virus) → will cause liver cancer. 4.Stomach cancer is highly prevalent in China, and there are other treatment means besides surgery. 5.Industrialization, accelerated pace of life, bowel cancer is rising year by year, less movement and more meat. 6.Tumor development may be half of genetic and half of lifestyle. 7, pay attention to change the bad lifestyle → to eat well, not to be obese, to quit smoking, to exercise more and not to sit down soon, not to eat moldy food.