Tumor Markers

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Tumor Markers

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What are tumor markers?

 Tumor markers are substances 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.

 More recently, the idea of what constitutes a tumor marker has

broadened. Newer types of tests have been developed that look for

changes in genetic material (DNA, RNA), rather than proteins, in patient samples. The genetic changes have been found to be associated with certain cancers and can be used as tumor markers.

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Limitations: While tumor marker tests can

provide very useful information, they do have limitations:

 none has sufficiently high sensitivity and specificity to be used to screen the general population

 few are specific for one type of cancer

 many are raised in non-cancerous conditions

 not all patients with a cancer of one type have raised concentrations in the bloodstream of its specific tumour marker

 some cancers have no associated tumour marker

 they cannot be used alone to diagnose cancer but must be considered in conjunction with a patient's medical history, physical examination and other laboratory and imaging tests.

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Types of Tumor Markers

Some of the more useful tumor markers:

 Prostate-specific antigen (PSA)

 Prostatic acid phosphatase (PAP)

 CA 125

 Carcinoembryonic antigen (CEA)

 Alpha-fetoprotein (AFP)

 Human chorionic gonadotropin (HCG)

 CA 19-9

 CA 15-3

 CA 27-29

 Lactate dehydrogenase (LDH)

 Neuron-specific enolase (NSE)

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Tumour marker test

 A biomarker is any cellular, molecular, chemical or physical change that can be measured and used to study a normal or abnormal process in the body. A change in the normal amount of a biomarker can help to check the risk for, presence of or progress of a disease or the effects of treatment.

 A tumour marker, like a biomarker, is a naturally occurring substance in the body. An increased amount of a tumour marker can indicate the

presence of a cancer. Some tumour markers are specific to one type of cancer, while others are related to several different types of cancer.

Tumour markers may also increase with non-cancerous conditions.

 A tumour marker can be made by cancer cells or by the body in response to cancer. Tumour markers are usually found in the blood or urine, but they can also be found in tumours and other tissue.

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Common tumor markers

 Some examples of common tumor markers include:

 CA15-3 is a tumor marker for breast cancer.

 CA19-9 antigen has been shown to be elevated in the blood of some patients with gastrointestinal tumors.

 CA-125 is a marker for monitoring disease progression in ovarian cancers.

 PSA is a marker for monitoring disease progression in prostate cancers.

 CEA (carcinoembryonic antigen) is useful in monitoring patients with various types of malignancies, such as gastrointestinal, pancreatic, breast, and lung cancers.

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What is HER2-positive breast cancer

 HER2-positive breast cancer is a breast cancer that tests positive for a protein called human epidermal growth factor receptor 2 (HER2), which promotes the growth of cancer cells.

 In about 1 of every 5 breast cancers, the cancer cells have a gene mutation that makes an excess of the HER2 protein.

 In some reports, HER2 is referred to as HER2/neu or ERBB2 (Erb-B2

receptor tyrosine kinase 2). Hormone receptors are identified as estrogen (ER) and progesterone (PR).

 HER2 is a gene that creates HER2 proteins, or receptors. These receptors help control growth and repair of breast cells. An overexpression of HER2 protein causes out-of-control reproduction of breast cells.