Tumor markers are a group of proteins or glycoproteins related to tumorigenesis and development, which are important in screening tumors and predicting the efficacy during tumor treatment. However, due to different detection methods and different standards of testing laboratory accusations, the specific values also differ greatly. Therefore, when interpreting the results of tumor markers, specific analysis should be made on a case-by-case basis to avoid errors. 1. The clinical significance of common tumor markers. Glycoprotein tumor markers: CA-199 is relatively specific for pancreatic cancer and bile duct cancer, CA-125 for ovarian cancer, CA-153 for breast cancer, CA-724 for gastric cancer, however, these markers are not completely specific and cross over each other. Protein: AFP (alpha-fetoprotein) for primary liver cancer, PSA for prostate cancer, and CEA for most adenocarcinomas. 2. How to view the increase of tumor markers. The author has encountered many patients who have inquired about the increase of a certain marker, some of them do have tumor occurrence, and some of them are just meaningless and mildly increased. Tumor markers are the results of quantitative testing of certain substances in serum, in fact, the normal values of these substances are also obtained by appropriate methods of calculation after testing for certain groups of people, and their specific values may have some overlap with those of very few patients. In other words, not everyone with cancer is elevated, nor is an elevation a cancer, but the specific situation must be determined in conjunction with the clinical situation. For example, AFP can be increased in cirrhosis and chronic active hepatitis, not only in liver cancer, and the positive rate of AFP in real liver cancer is only about 80%, while the remaining 20% are not increased. Therefore, the diagnosis must be confirmed by clinical analysis and, if necessary, ultrasound, CT, endoscopy and other relevant examinations. However, there are several cases that must be given full attention, one is dynamic and continuous increase of tumor markers, the second is a single tumor marker significantly increased, the third is a familial genetic history of tumor screening when tumor markers are increased. In these cases, it is important to see a specialist to identify the cause.