CA 125

Cancer antigen 125, a protein normally made by certain cells in the body, including those of the ovaries, Fallopian tubes, uterus, cervix, and lining of the chest and abdominal cavities (the pleura and peritoneum). When CA 125 is found in higher than normal amounts (more than 35 kU/ml), it is considered a marker for cancer. Benign conditions that can raise CA 125 include infections of the lining of the abdomen and chest, menstruation, pregnancy, endometriosis, and liver disease. Benign tumors of the ovaries can also cause abnormal test results.