In gastrointestinal tumors, CEA, CA199, CA72.4, CA125, CA242, etc. are commonly examined. Generally speaking, the sensitivity and specificity of these indicators are getting lower and lower since they go there, but the abnormal items are different for each patient, some have high CA72.4, some have high CA125, and some patients do not have any of these indicators since the beginning (accounting for about 10%), such patients, their tumor markers are not significant for their future judgment of recurrence and metastasis and treatment efficacy estimation. Patients with elevated tumor markers have poor clinical prognosis, suggesting that local tumor spread or distant metastasis has occurred. It is more meaningful to observe their dynamic changes. If CEA is elevated when the patient is diagnosed with colon cancer, and it decreases to normal after 1-2 months of surgery (usually after 1 month of surgery), it indicates that the tumor is relatively cleanly resected and the chance of distant metastasis is small, if it increases again in future treatment, it reminds the doctor that there may be the possibility of recurrence and metastasis, and its progressive increase must be observed to be examined in detail. Some scholars observe that if the elevation of tumor markers is preceded by imaging. Then the time to the appearance of imaging lesions can be 3-6 months. For example, the markers for esophageal squamous carcinoma are very special, and the ones commonly used in clinical practice are CEA, SCC, NSE, CYFRA211, etc. The magnitude of their changes is very small, unlike CEA and CA199 in other gastrointestinal cancers, so the clinical specificity and sensitivity are poor. Therefore, the significance of blood tumor markers for esophageal squamous cancer is poor for diagnosis, prognosis and evaluation of efficacy. AFP (alpha-fetoprotein) is a specific indicator of primary hepatocellular carcinoma (HCC) and has high sensitivity in the diagnosis of HCC, but there are very few patients with special types of gastric cancer who have high AFP, which is called “hepatic gastric cancer” and has very poor prognosis. What should I do if I find high tumor markers in medical checkup? For example, smoking, alcohol consumption, diarrhea, pancreatitis, diabetes mellitus and abnormal liver function can be elevated, and there are also unexplained elevations.