Cancer may have a genetic predisposition, but most simply increase the chances of developing cancer. Cancer is also associated with long-term stimulation by biological, physical, pharmacologic, and environmental factors. Cancer is defined as a malignant tumor originating in epithelial tissue. It has been shown that although cancer may be hereditary, it does not mean that cancer is a hereditary disease, nor does it indicate that its immediate family members will necessarily develop the disease. Regarding the heredity of cancer, it usually only means that one’s own chances of suffering from cancer are higher than those of people with no family history. Secondly, the development of cancer does not depend solely on genetic factors, but mainly occurs when a number of factors come together. Therefore, besides genetic factors, cancer is also related to biological factors such as viruses and bacteria, physical factors such as ionizing radiation and ultraviolet radiation, drugs such as cytotoxicity and immunosuppressants, and environmental factors such as air pollution and smoking. If a patient is detected with cancer, he/she can cooperate with the doctor to do further relevant examinations to clarify the cause of the disease and then carry out standardized treatment.