Tumor marker test
What is a tumor marker test?
A tumor marker test is one of the tools used to detect cancer. As the levels of specific tumor markers or biochemicals are almost always raised when there is development of specific cancerous growth within the body, it can help to spot any abnormal growth within the body. Unfortunately, tumor markers can provide definite indication only when the cancer has spread substantially.
Why is it conducted?
One of the reasons why these tests are conducted is that it can help to indicate the possibility of widespread cancer in an individual. They are therefore conducted to:
- Check for a particular cancer as different cancers produce different antigens.
- To get an understanding of the future course of the disease.
- Check the response of the cancer to the treatment being given.
Who should go for it?
As tumor marker tests are not very sensitive tests, they are not recommended for general screening of people who have a high risk of developing cancer. It is used for the following purposes.
- Persons who are undergoing treatment for cancer are often advised this test as the increase in tumor markers directly indicates an increase in the severity of the cancer. This helps to follow up the efficacy of the treatment being given.
- Specific tumor markers can be used in certain cases to clearly identify the type of cancer.
- People who have recurrent cancers that may return after sometime are advised the tumor marker test to confirm whether there has been any reoccurrence.
This is a simple blood or urine test. The choice of the specific tumor marker test depends on the suspected cancer.
Interpretation of results
An important point to remember is that these tests are not conclusive in themselves as the same proteins exist in the body when there may be a non-malignant tumor. They indicate the necessity of further correlating evidence through biopsy. The situation is further complicated by the fact that these antigens may also be increased in the body in some other diseases. But specific tumor marker tests can help to confirm the type of cancer that has developed in the body.
- Alpha-fetoprotein (AFP): liver cancer
- Anaplastic lymphoma kinase (ALK): some lung cancers
- BCR-ABL: Chronic myeloid leukemia (CML)
- B2M: multiple myeloma, CLL or chronic lymphocytic leukemia, lymphomas
- Bladder tumor antigen (BTA): bladder cancer
- BRAF: melanoma, thyroid cancer, colorectal cancer
- CA 15-3: breast cancer
- CA 19-9: colorectal cancer, pancreatic cancer
- CA 27-29: breast cancer
- CA125: ovarian cancer
- Calcitonon: medullary thyroid carcinoma
- Carcinoembryonic antigen (CEA): prognosis assessment of colorectal cancer
- Chromogranin A (CgA): neuroendocrine tumors
- Epidermal growth factor receptor (EGFR/ HER1): for prognosis assessment
- HE-4: ovarian cancer
- HER 2/ EGFR 2: prognosis of breast cancer
- Human chorionic gonadotropin (HCG): some testicular and ovarian cancers
- Neuron-specific enolase (NSE): neuroendocrine tumors
- Prostate-specific antigen (PSA): prostate cancer
- Prostatic acid phosphatase (PAP): prostate cancer
- Thyroglobulin-thyroid cancer
- S-100: melanoma
These are just some of the tumor marker tests used to help diagnose or examine the prognosis of cancer. There are other tests available too that are used to confirm rare types of cancers.
Written by: Nandita tripati
Date last updated: January 07, 2015