Ovarian Tumor Marker (CA 125) - Cancer Antigen 125 (CA 125) Test

The cancer antigen 125 (CA 125) serum test measures the level of a glycoprotein known as MUC16. It is naturally produced by serous (tissue) cells that line body cavities such as the chest and abdomen. Its levels are significantly elevated in serous ovarian cancer (the most common type), as well as in other cancers. It can also be elevated in many benign (non-cancerous) conditions and inflammatory diseases, severely limiting its usefulness in general screening for healthy women.