Tumor markers


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Tumor markers

  1. 1. Tumor Markers Definition Tumor markers are substances that are produced by cancer or by other cells of the body in response To cancer or certain benign (non cancerous) conditions. Most of the tumor marker are made by normal cells as well as by cancer cells however, they are produced at much higher levels in cancerous conditioners These substances can be found in blood ,urine,stool,tumor tissue or other tissue or body fluids of some patient with cancer Most of tumor markers are protein in nature. Recently , pattern of gene expression and changes to DNA also begin to be used as tumor markers 20 Different type of tumor markers are in clinical use. Some are associated with one type of cancer while other are associated with different types of cancer i.e 1 or 2 type of cancer. No universal tumor marker that can detect any type of cancer. There are some limitations to tumor markers.Sometimes non-cancerous conditioners can cause the level of certain tumor markers to increase. In addition,not every with a particular type of tumor cancer will have increaselevel of a tumor marker associated with that cancer. Tumor marker have not been identified for each type of cancer. Examples of TUMOR MARKERS 1. HE-4 2. HER2 (or HER2/neu, erbB-2, or EGFR2) in breast cancer
  2. 2. 3. 4. 5. 6. Lactate dehydrogenase (LDH) S-100 (in mylenomas) Prostate-specific antigen (PSA) CA 15-3 Application of Tumor Markers Screening:-To identify patients with early cancer Staging/Prognosis:- To assess the risk and predict the outcomes Surveillance:-To detect recurrence duringfollow up Monitoring:-To evaluate the response treatment Therapy:-Targeting therapy. Measurement of tumor markers are usuallycombined with biopsies,to diagnose cancer. Tumor markers tells about stage i.e prognosis , So before treatment level of tumor markers must be checked. Tumor markers are checked during after the therapy of cancer to determine determine either cancer is responding or not. Increase Level tumor marke>>>>>>>> No response Decrease Level of tumor markers>>>>> Responding How measured Dr take sample of tumor tissue or body fluid and measure its level PSA level is determined by Blood analysis B2-microglubulin B2M level for Mutiplemyelema is determined by Blood urine and CSFanalysis.
  3. 3. If the tumor markers is being used to determine whether the treatment is working or whether there is a recurrent, the marker will be measured over time Serial measurementWhich show whether the level of marker is staying same or decreasing are more meaningful than a single measurement Tests for tumor markers. ELISA Pitfalls in immunoassays Example : Prostate-specific antigen (PSA) PSA is a tumor marker for prostate cancer. PSA is a protein made by cells of the prostate gland,which is found only in men. The level of PSA in the blood can be elevated in prostate cancer, but PSA levels can be affected by other things, too. Men with benign prostatic hyperplasia (BPH), a non-cancerous growth of theprostate, often have higher levels. The PSA level also tends to be higher in older men and thosewith infected or inflamed prostates. It can also be elevated for a day or 2 after ejaculation. PSA is measured in nanograms per milliliter (ng/mL). blood PSA level below 4 ng/mL(cancer is unlikely). Levels higher than 10 ng/mL ( cancer is likely or also called hitological value). The area between 4 and 10 is a gray zone. Men with PSA levels in this borderline range have about a 1 in 4 chance of having prostate cancer. A doctor may recommend a prostate biopsy (getting samples Of prostate tissue to look for cancer) for a man with a PSA level above 4 ng/mL. The PSA test is very valuable in monitoring the response to treatment and in the follow-up of menwith prostate cancer. In men who have been treated with surgery meant to cure the disease, the PSA should fall to an undetectable level. The PSA should also go down after treatment with radiation therapy (although it doesn’t go away completely). A rise in the PSA level may be a sign
  4. 4. the cancer is coming back. Cost 350 The drawbacks of tumor markers A simple blood test that could find cancers in their earliest stages could prevent the deaths of millions of people. But very few tumor markers are useful for finding cancer at a very early stage. There are a few reasons for this: Almost everyone has a small amount of these markers in their blood, so it’s very hard to spot early cancers by using these tests. The levels of these markers tend to get higher than normal only when there’s a large amount of cancer present. Some people with cancer never have high tumor marker levels. Even when levels of these markers are high, it doesn’t always mean cancer is present.