Patients with malignant tumors need to do a series of examinations for consultation, including questioning, whether there is any discomfort, which needs to be examined carefully, and physical examination, which is then judged by the simple examination methods of doctors. After the initial examination, further tumor related examinations need to be done, such as tumor marker examination, imaging examinations, such as ultrasound, X-ray, CT, MRI, and even PET-CT examination. There are also some endoscopic examinations, such as gastroscopy, enteroscopy, fibrinoscopy, nasopharyngoscopy and a series of other examinations, even including taking biopsy for pathological examination, which can be done for mass excision biopsy, lymph node excision biopsy, doing endoscopic tissue plus biopsy, mass puncture biopsy. There are also cytological examinations of pleural fluid, ascites, hydrocephalus, and pericardial fluid. These are some of the ways to do pathological examination, and pathological results are the gold standard for diagnosing cancer.