Tumor Marker CA 125: What it Means

What exactly is CA 125?

The tumor marker CA 125, short for Cancer Antigen 125, is a so-called monoclonal antibody. Biochemically, it is defined as a glycoprotein – in other words, it is a protein with sugar residues attached. The physician can determine CA 125 from blood plasma, blood serum and cerebrospinal fluid (CSF).

Standard values for CA 125

When is the CA 125 elevated?

• Ovarian cancer (ovarian carcinoma)
• Cancer of the endometrium (endometrial carcinoma)
• Cancer of the cervix (cervical carcinoma)
• Breast cancer (mammary carcinoma)
• Pancreatic cancer (pancreatic carcinoma)
• Liver cell cancer (hepatocellular carcinoma)
• Biliary tract cancer
• Stomach cancer (gastric carcinoma)
• Colon cancer (colon carcinoma)
• Lung cancer (bronchial carcinoma)

Some benign conditions can also cause CA 125 levels to rise. These include, for example:

• acute inflammation of the adnexa (fallopian tubes and ovaries)
• peritonitis (inflammation of the peritoneum)
• Kidney failure
• Inflammation of the pancreas (pancreatitis)
• gallstones (cholelithiasis)
• chronic liver diseases such as hepatitis or cirrhosis

In addition, slight elevations of the tumor marker are found during pregnancy. This is quite normal in this context and is not a compelling indication of disease.

When is the CA 125 determined?

How useful is the determination of the tumor marker?

The CA 125 is quite reliable in the diagnosis of ovarian cancer: In early stages of the disease, elevated values are found in up to 60 percent of women with the disease, and in late stages in almost all of them. Therefore, in contrast to many other tumor markers, CA 125 is already useful for diagnostics.

Apart from the diagnosis, the oncologist (cancer specialist) determines the tumor marker in the further course of the disease in patients with known ovarian cancer. The development of the CA 125 values enables him to get an idea of the progression of the disease or the success of the current therapy.