There are three reasons why CA125 is high

CA125 is a glycoprotein that was discovered by Bast et al. in 1981 from the epithelial ovarian cancer antigen test and can be fused to the monoclonal antibody OC125. It comes from the renal tubular epithelial cells of in vitro fertilized embryos and is not present in normal ovarian tissue. Therefore, it is most common in the blood cells of patients with epithelial ovarian tumors (plasmatoid tumors). Its diagnostic sensitivity is high, but its specificity is weak. It is not present in mucinous utero-ovarian tumors.

1. Features

CA125 is an antigen that can be identified by a monoclonal antibody (named OC125) obtained by immunizing mice with ovarian plasma cystadenocarcinoma and hybridizing them with myeloma cells. It is a transmembrane glycoprotein located in the chromosome 19p13.2 region with 5797 base pairs and belongs to IgG1. Because its amino acid sequence has some characteristics of mucin molecules, it was named CA125 (gene is MUC16), and it has been confirmed through transfection technology that MUC16 is CA125. The relative molecular mass of CA125 is 200,000 to 1 million. It is a high molecular weight glycoprotein with a ring-shaped structure and contains 24% glycogen. It is a glycoprotein nitric oxide synthase similar to mucin and belongs to IgG. The CA125 concentration in healthy adults is lower than 35U/mL.

2. Reasons for higher CA125

1. The CA125 level in the blood cells of patients with ovarian cancer increases significantly, while the CA125 level decreases rapidly in those who receive reasonable radiotherapy, chemotherapy and surgical treatment. If an attack occurs, CA125 may rise before clinical manifestation.

2. Other non-uterine and ovarian malignant tumors also have a certain detection rate, such as breast cancer 40%, pancreatic cancer 50%, gastric cancer 47%, lung cancer 44%, colorectal cancer 32%, and other gynecological tumors 43%. For lung cancer patients, the detection rate of CA125 increases significantly with the progress of lung cancer staging. Clinical experiments show that the detection rate for stage I lung cancer is 7.8%, the detection rate for stage II is 18.6%, the detection rate for stage III is 32.5%, the detection rate for stage IV is 53.9%, and the overall detection rate is 26.9%.

3. Although non-malignant tumors such as endometriosis, pelvic inflammatory disease, ovarian cysts, pancreatitis, hepatitis, and cirrhosis have increased to varying degrees, the detection rate is relatively low.