Cancer is a serious disease that endangers human health, and early diagnosis and treatment are very important, usually the following tests are used to determine whether cancer has occurred: i. Blood tests, such as tumor marker test and circulating tumor cell test, when cancer occurs, tumor markers will increase abnormally, and circulating tumor cell test will be significantly higher than normal; ii. Imaging examinations such as ultrasound, CT, MRI, PET-CT, etc., will show corresponding performance when there are cancer lesions in the body; fourth, pathological examinations, when abnormal masses are found in the body, in addition to the above examinations, pathological examinations can also be performed to clarify the diagnosis as soon as possible. To sum up, people with high risk of cancer should undergo the above examinations regularly to detect and treat cancer as early as possible.