A tumor marker refers to a substance that is characteristically present in a malignant tumor cell, or is abnormally produced by a malignant tumor cell, or a substance produced by a host's stimulating reaction to a tumor, and can reflect tumor occurrence and development. A class of substances that monitor the response of a tumor to treatment. Tumor markers are present in the tissues, body fluids, and excretions of tumor patients and can be detected by immunological, biological, and chemical methods.
Common physical examination items can be divided into the following categories: 1. Serum carcinoembryonic antigen (CEA): normal value is less than or equal to 3.45 micrograms / liter. Initially found in patients with colon cancer, elevated CEA, and later found that in gastric cancer, urinary tract cancer, ovarian cancer, lung cancer, pancreatic cancer, breast cancer, medullary thyroid carcinoma, bladder cancer and cervical cancer, 30% of patients with blood CEA is elevated. 2. Alpha-fetoprotein (AFP): AFP is the earliest discovered tumor marker and a common examination for the diagnosis of primary liver cancer. About 87% of patients with primary liver cancer have AFP of more than 20 μg/L. 3. Prostate specific antigen (PSA): normal value is less than 4 micrograms / liter, the positive rate in prostate cancer is as high as 30% to 86%, and its elevated level is closely related to the tumor.