A tumour marker is basically a substance (often proteins) that is present or produced by cancer cells or other cells of the body in response to cancer. Although cancer cells often produce tumour markers, healthy cells in the body may also produce them as well.
Tumour markers are substances (often proteins) that are produced by the cancer tissue itself or sometimes by the body in response to cancer growth. These substances are detected from body samples such as blood, urine, and tissue. These markers along with some tests can be used to help detect and diagnose some types of cancer and to monitor a person’s response to certain treatments.
You may need a tumour marker test if you are currently being treated for cancer, having finished a cancer treatment or if you have a high risk of developing cancer because of genes or other reasons.
The type of tests depends on your health, health history and symptoms you may have. Below are some of the most common types of tumour markers and what they are used for.
- CA 125 (cancer antigen 125)
- CA 15-3 and CA 27-29 (cancer antigens 15-3 and 27-29)
- PSA (prostate-specific antigen)
- CEA (carcinoembryonic antigen)
- AFP (Alpha-fetoprotein)
- CA 19-9 (cancer antigen 19-9)
While tumor marker tests can provide very useful information, they do have limitations:
- Many tumor markers may also be elevated in persons with conditions or diseases other than cancer.
- Some tumor 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 tumor marker.
- Not every cancer has a tumor marker that has been identified as associated with it.
How to Identify?
A doctor takes a sample of tumor tissue or bodily fluid and sends it to a laboratory, where various methods are used to measure the level or presence (or absence) of the tumor marker.
If the tumor marker is being used to determine whether treatment is working or whether there is a recurrence, the marker’s level will be measured in multiple samples taken at different times during and after treatment. Usually “serial measurements,” which show how the level of a marker is changing over time, are more meaningful than a single measurement.
There is very little risk to having a blood test. You may have slight pain or bruising at the spot where the needle was put in, but most symptoms go away quickly.
There is no risk to a urine test.
If you have had a biopsy, you may have a little bruising or bleeding at biopsy site. You may also have a little discomfort at the site for a day or two.
What to Do?
There are different ways to test for tumor markers. Blood tests are the most common type of tumor marker tests. Urine tests or biopsies may also be used to check for tumor markers. A biopsy is a minor procedure that involves removing a small piece of tissue for testing.
- Blood test
- Urine Test
Once the test is finished, the result will help diagnose the type of cancer, show whether cancer treatment is working and show if your cancer has returned after treatment.