CA 15-3 Tumor Marker

CA15-3 is a substance, which is used in diagnosis of certain malignant diseases. Such compounds are called tumor markers.


CA 15-3 is a glycoprotein, which occurs particularly in the cells of mammary glands. Its concentration in blood may be measured in a laboratory from a sample of venous blood.


Serum CA 15-3 is usually increased in certain forms of breast cancer. Of course, the diagnosis must be confirmed by other examination methods  such as ultrasound, mammography or computed tomography supported by fine-needle biopsy. The main use of CA 15-3 is in monitoring patients who have been diagnosed with breast cancer and undergo chronic treatment. According to the actual level of CA 15-3, we may assume the effectiveness of the treatment and the possibility of tumor recurrence (elevation of CA 15-3).


The main disadvantage of CA 15-3 is its lower reliability, but this is a problem with most tumor markers. This means that many patients with breast cancer may have absolutely normal level of CA 15-3 and on the contrary, some non-malignant conditions may cause its elevation (acute and chronic liver inflammation, chronic renal failure, chronic bronchitis, and others.


Jiri Stefanek, MD  Author of texts: Jiri Stefanek, MD
 Sources: basic text sources