Tumor marker tests



Definition

Tumor markers are a group of proteins, hormones, enzymes, receptors, and other cellular products that are overexpressed (produced in higher than normal amounts) by malignant cells. Tumor markers are usually normal cellular constituents that are present at normal or very low levels in the blood of healthy persons. If the substance in question is produced by the tumor, its levels will be increased either in the blood or in the tissue of origin.


Purpose

The majority of tumor markers are used to monitor patients for recurrence of tumors following treatment. In addition, some markers are associated with a more aggressive course and higher relapse rate and have value in staging and prognosis of the cancer. Most tumor markers are not useful for screening because levels found in early malignancy overlap the range of levels found in healthy persons. The levels of most tumor markers are elevated in conditions other than malignancy, and are therefore not useful in establishing a diagnosis.


Precautions

Tumor markers are sometimes elevated in nonmalignant conditions. Not every tumor will cause a rise in the level of its associated marker, especially in the early stages of some cancers. When a marker is used for cancer screening or diagnosis, the physician must confirm a positive test result by using imaging studies, tissue biopsies, and other procedures. False positive results may occur in laboratory tests when the patient has cross-reacting antibodies that interfere with the test.


Description

Physicians use changes in tumor marker levels to follow the course of a patient's disease, to measure the effect of treatment, and to check for recurrence of certain cancers. Tumor markers have been identified in several types of cancer, including malignant melanoma; multiple myeloma; and bone, breast, colon, gastric, liver, lung, ovarian, pancreatic, prostate, renal, and uterine cancers. Serial measurements of a tumor marker are often an effective means to monitor the course of therapy. Some tumor markers can provide physicians with information used in staging cancers, and some help predict the response to treatment. A decrease in the levels of the tumor marker during treatment indicates that the therapy is having a positive effect on the cancer, while an increase indicates that the cancer is growing and not responding to the therapy.


Types of tumor markers

There are five basic types of tumor markers.


ENZYMES. Many enzymes that occur in certain tissues are found in blood plasma at higher levels when the cancer involves that tissue. Enzymes are usually measured by determining the rate at which they convert a substrate to an end product, while most tumor markers of other types are measured by a test called an immunoassay. Some examples of enzymes whose levels rise in cases of malignant diseases are acid phosphatase, alkaline phosphatase, amylase, creatine kinase, gamma glutamyl transferase, lactate dehydrogenase, and terminal deoxynucleotidyl transferase.

TISSUE RECEPTORS. Tissue receptors, which are proteins associated with the cell membrane, are another type of tumor marker. These substances bind to hormones and growth factors, and therefore affect the rate of tumor growth. Some tissue receptors must be measured in tissue samples removed for a biopsy, while others are secreted into the extracellular fluid (fluid outside the cells) and may be measured in the blood. Some important receptor tumor markers are estrogen receptor, progesterone receptor, interleukin-2 receptor, and epidermal growth factor receptor.

ANTIGENS. Oncofetal antigens are proteins made by genes that are very active during fetal development but function at a very low level after birth. The genes become activated when a malignant tumor arises and produce large amounts of protein. Antigens comprise the largest class of tumor marker and include the tumor-associated glycoprotein antigens. Important tumor markers in this class are alpha-fetoprotein (AFP), carcinoembryonic antigen (CEA), prostate specific antigen (PSA), cathespin-D, HER-2/neu, CA-125, CA-19-9, CA-15-3, nuclear matrix protein, and bladder tumor-associated antigen.

ONCOGENES. Some tumor markers are the product of oncogenes, which are genes that are active in fetal development and trigger the growth of tumors when they are activated in mature cells. Some important oncogenes are BRAC-1, myc, p53, RB (retinoblastoma) gene (RB), and Ph 1 (Philadelphia chromosome).

HORMONES. The fifth type of tumor marker consists of hormones. This group includes hormones that are normally secreted by the tissue in which the malignancy arises as well as those produced by tissues that do not normally make the hormone (ectopic production). Some hormones associated with malignancy are adrenal corticotropic hormone (ACTH), calcitonin, catecholamines, gastrin, human chorionic gonadogropin (hCG), and prolactin.


Tumor markers in clinical use

Currently, there are over 60 analytes that are used as tumor markers. All of the enzymes and hormones mentioned above have been approved as tumor markers by the Food and Drug Administration (FDA), but most of the others are not; they have been designated for investigation purposes only. The following list describes the most commonly used tumor markers approved by the FDA for screening, diagnosis, or monitoring of cancer.

Preparation

Determination of the circulating level of tumor markers requires a blood test performed by a laboratory scientist. A nurse or phlebotomist usually draws the patient's blood; he or she ties a tourniquet above the patient's elbow, locates a vein near the inner elbow, cleanses the skin overlying the vein with an antiseptic solution, and inserts a sterile needle into that vein. The blood is drawn through the needle into an attached vacuum tube. Collection of a blood sample takes only a few minutes.

Tissue samples are collected by a physician at the time of surgical or needle biopsy. A urine sample is collected by the patient, using the midstream void technique.


Aftercare

Aftercare following a blood test consists of routine care of the area around the puncture site. Pressure is applied for a few seconds and the wound is covered with a bandage. If a bruise or swelling develops around the puncture site, the area is treated with a moist warm compress.


Risks

The risks associated with drawing blood include dizziness, bruising, swelling, or excessive bleeding from the puncture site. As previously mentioned, the results of blood tests should be interpreted with caution. A single test result may not yield clinically useful information. Several laboratory reports over a period of months may be needed to evaluate treatment and identify recurrence. Positive results must be interpreted cautiously because some tumor markers are increased in nonmalignant diseases and in a small number of apparently healthy persons. In addition false negative results may occur because the tumor does not produce the marker, and because levels seen in healthy persons may overlap those seen in the early stages of cancer. A false positive result occurs when the value is elevated even though cancer is not present. A false negative result occurs when the value is normal but cancer is present.


Normal results

Reference ranges for tumor markers will vary from one laboratory to another because different antibodies and calibrators are used by various test systems. The values below are representative of normal values or cutoffs for commonly measured tumor markers.

Resources

books

Burtis, C.A., and E.R. Ashwood, eds. Tietz Fundamentals of Clinical Chemistry , 5th ed. Philadelphia, PA: Saunders, 2001.

Henry, J.B., ed. Clinical Diagnosis and Management by Laboratory Methods , 20th ed. Philadelphia, PA: Saunders, 2001.

"Tumor Immunology." Section 11, Chapter 143 in The Merck Manual of Diagnosis and Therapy , edited by Mark H. Beers, MD, and Robert Berkow, MD. Whitehouse Station, NJ: Merck Research Laboratories, 1999.

Wallach, Jacques. Interpretation of Diagnostic Tests , 7th ed. Philadelphia, PA: Lippincott Williams & Wilkens, 2000.


organizations

American Cancer Society. 1599 Clifton Rd. NE, Atlanta, GA 30329-4251. (800) 227-2345. http://www.cancer.org .

American Society of Clinical Oncology (ASCO). 1900 Duke Street, Suite 200, Alexandria, VA 22314. (703) 299-0150. http://www.asco.org .

National Cancer Institute (NCI). NCI Public Inquiries Office, Suite 3036A, 6116 Executive Boulevard, MSC8332, Bethesda, MD 20892-8322. (800) 4-CANCER or (800) 332-8615 (TTY). http://www.nci.nih.gov .

United States Food and Drug Administration (FDA). 5600 Fishers Lane, Rockville, MD 20857-0001. (888) INFO-FDA. http://www.fda.gov .

other

Abbott Laboratories. http://www.abbottdiagnostics.com/medical_conditions/cancer/index.htm/ .

National Institutes of Health. http://www.nlm.nih.gov/medlineplus/encyclopedia.html [cited April 5, 2003].

Tumor Marker Tests. http://www.secundus.vh.org/adult/patient/cancercenter/tumormarker/index.html July, 2002 [cited April 4, 2003].


Victoria E. DeMoranville Mark A. Best



User Contributions:

1
carol kelder
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Feb 3, 2009 @ 10:10 am
All though i didn't understand all of the terms used.I felt a sense of relief to know my sister has the best care she could have.!!Thank GOD for People like you all.I prey patty lives along and healthy life.Even if she isn't all that well now .I PREY she gets well in your hands.GOD BLESS YOU ALL .Carol Kelder
2
hitesh
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Oct 14, 2009 @ 6:06 am
CEA is produced in fetal develpoment. but what is roll of CEA production.
whatkind of develpoment.
what is exact roll of CEA production
3
Ankit
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Feb 2, 2010 @ 10:10 am
This is very useful article for me b'coz i really needd it. I want other information reguarding tumor marker tests so please send me if possible.

Thank you.
4
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Mar 21, 2010 @ 3:15 pm
what is the most recent tumor markers rather than afp
5
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May 27, 2010 @ 9:09 am
This is the most useful material I can find on the internet! It helped me a lot with me final thesis on tumor marker!
6
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Jun 27, 2010 @ 3:15 pm
my sister had a tumor marker test done which came back high she went into hospital for investigation nd the dotor foung a load of adheasions in her stomach up her chest wall attached to her bladder and all around her organs she is in great form and only she had pains in her sides would never of had an investigation what do you think is wrong with her as i am now very worried any information would be helpful. she has to return to hospital to have these removed he said then they would talk about getting rid of the ones around the chest.
7
NAMITA
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Oct 25, 2010 @ 2:02 am
TUMOUR MARKER TEST REPORT
TOTAL PSA CMIA VALUE = 721.843 ng/ml
My question is as in your article you have mentioned that Persons with a borderline total PSA (between 4–10 ng/L), but who have a low free PSA are more likely to have malignant prostate disease. Does this high value confirm to have negative malignant prostate disease?
8
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Nov 1, 2010 @ 5:17 pm
i was diagnose with testicular cancer back on 2007 went trough surgery and radiation and then they increase my insurance policy and no work with these economy so i went to mexico to have the AFP tumor reading and it reads 3.4 and the range is 0.0-8.0ng/ml i think thats very good thanks for the article.i have no insurance coverage GOD BLESS YOU.
9
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Mar 1, 2011 @ 1:13 pm
please send me other informations regarding testicular tumor markers,I found the article very useful,intrusting and informative. Thanks
10
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Apr 2, 2011 @ 6:18 pm
good evening:
I have been told that I have a tumor in my fatty liver which I will be getting a liver biopsy for soon. But my bloodwork keeps coming back normal. what does this mean. Thank you , Anne marie Spring
11
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Aug 8, 2011 @ 4:04 am
I find your site very informative
Interesting reading. I spend a lot of time on your site.
Your site makes for some good reading
I found your site educational and interesting
12
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Sep 24, 2011 @ 11:11 am
How long will CA-125 markers stay elevated after radiation? I have had three surgeries, three chemo treatments and radiaton for ovarian cancer stage 3. The CA-125 is bouncing back and forth after radiation. The first one was around three monts after and it was 64. Then aroun five weeks later it is 96. Could it be that the radiation is still affecting it? Thanks
13
Wildhacker
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Oct 30, 2012 @ 3:03 am
Like Jim I too was diagnosed with Cancer of patosrte in my 70s and was put onto `Watchful Waiting` and told that I would not `die of it` but that I would `die with it.` I had to retire from nursing after completing 58yrs. but I refused to accept the `watchful waiting verdict` and, as Jim did, I became involved in research advances made in the treatment of cancer of the patosrte and found that a breakthrough had been made by a brilliant Urological Surgeon in Basingstoke and I contacted him and he offered to take me onto his trial despite my age . It had been long, inconvenient and uncomfortable for me as well as the expense of traveling to Basingstoke and staying overnight but after a year I am free of the curse of Cancer and have only one more review in the New Year and will have no need to attend further if I am still clear. Do not accept your GPs opinion on your condition. Search elsewhere and try to find where there has been an advance or breakthrough made and ask to be involved. GET A LIFE?? Cliff Charlesworth RGN. RMN. RNMH
14
ladan
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Apr 9, 2013 @ 4:04 am
dear scientific team

this article was so useful for me but i want to know exactly that TUMOR MARKER have to be tissue specific to use as a screening marker in tissue biopsy?
15
abeer mohamed
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Sep 3, 2014 @ 4:04 am
is it contraindication to take chemotherapy during taking samples of hepatic tumours markers?
16
Neethu
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Jun 6, 2015 @ 11:11 am
My father's Alpha protein test result is higher than 800 in blood testing.He is a Liver cirrhosis patient.I want to know that it's a treatable stage or not?can possible to reduce the count of AFP test in blood?plz..give me a advise from docters side and answers to these questions?
17
Mima
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Oct 22, 2015 @ 12:12 pm
what is the explanation of having the markers stable after about 2 weeks & during treatment?
18
Linda ROBERTS
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Oct 19, 2016 @ 10:10 am
my husband has cirrhosis of liver. A Ct scan showed a 5.7x5.3 mass in left lobe concerning for hepatocellular carcinoma. His AFP came back over 19,000. What should next step be to determine if he has HCC? MRI or PET Scan to diagnose if cancer or not?

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