What are tumour markers?
Tumour markers are substances, often proteins, that are produced by the cancer tissue itself or sometimes by the body in response to cancer growth. Because some of these substances can be detected in body samples such as blood, urine and tissue, these markers may be used, along with other tests and procedures, to help detect and diagnose some types of cancer, predict and monitor a person’s response to certain treatments, and detect recurrence.
While tumour marker tests can provide very useful information, they do have limitations:
- Many tumour markers may also be elevated in persons with diseases other than cancer.
- Some tumour markers are specific for a particular type of cancer, while others are seen in several different types of cancer.
- Not every person with a particular type of cancer will have an elevated level of the corresponding tumour marker.
- Not every cancer has a tumour marker that has been identified as associated with it.
Consequently, tumour markers alone are not diagnostic for cancer; for some types of cancer, they provide additional information that can be considered in conjunction with a patient’s medical history and physical exam as well as other laboratory and/or imaging tests.