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Breast cancer markers
Last reviewed: 23.04.2024
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Analysis for mammary cancer markers - immunochemical blood test - is performed during the diagnosis and treatment of breast tumors, along with diagnostic procedures such as mammography, ultrasound, computed tomography (CT), magnetic resonance imaging (MRI).
To make the correct diagnosis and prescribe the appropriate treatment is possible only on the basis of the aggregate of the data of the hardware examination and the interpretation of the blood test for oncomarkers.
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Breast Cancer Markers: CA 15-3
Mutated cancer cells synthesize a protein (high-molecular glycoprotein and O-linked oligosaccharide chains), which the body perceives as an antigen-a foreign element. This cancer antigen (cancer antigen, CA) penetrates into the blood and lymphatic vessels and circulates with blood and lymph flow. That is, if there is a malignant tumor, CA can be detected with a blood test.
Cancer markers of cancer of the breast are identified - cancer antigen 15-3 (CA 15-3) and cancer antigen 27-29 (CA 27-29). Domestic oncologists consider CA 15-3 to be specific to cancerous antigens in primary malignant breast tumors, although it is known that CA 15-3 is also elevated in the blood serum for lung, colon, pancreatic, liver, ovarian, cervical and endometrial cancers.
Doctors prescribe to pass an analysis for breast cancer markers not only for the purpose of differentiation of breast cancer and benign tumors, but also to track the course of already diagnosed pathology, to evaluate the effectiveness of the therapy, and to detect metastases of cancer.
To determine the cancer antigen, take blood from the vein (on an empty stomach, not earlier than 8 hours after the last meal) and subject it to immunochemical examination. The norm of cancer markers of the breast CA 15-3 is up to 26,9 U / ml, in foreign clinics the upper limit of the normal range is 30 U / ml.
Breast Cancer Markers: CA 27.29
In the American Society of Clinical Oncology (ASCO), the only analysis of blood that is specific for breast cancer is the analysis for breast cancer markers CA 27-29.
Test CA 27-29 measures the serum level of the soluble form of the glycoprotein MUC1, which is expressed on the envelopes of most breast carcinoma cells. The norm of breast cancer markers CA 27-29 is less than 38-40 U / ml.
The sensitivity of this oncomarker, according to experts, is also not high enough: the result is higher than normal with endometriosis, ovarian cyst, in the first trimester of pregnancy, with benign diseases of the breast, kidneys and liver.
Breast cancer markers: REA
Abroad, patients with breast pathologies give one more analysis - a test for carcinoembryonic antigen (carcinoembryonic antigen, CEA). In domestic clinical practice, it is called the cancer marker REA - cancer-embryonic antigen.
Oncologists say that in order to establish the correct diagnosis, it is necessary to combine the definition of the cancer cancer marker CA 15-3 with the detection of cancer-embryonic antigen in the blood of CEA. This antigen after birth practically disappears, and it is difficult to detect it in the serum of adult healthy people. Norm of oncomarker REA - up to 5 ng / ml.
But when cancerous diseases (especially with cancer of the rectum, lungs, breast, ovaries, pancreas, prostate and metastases to the liver and bone tissue), the cancer embryonic antigen grows up to 20 ng / ml and more. In this case, more than a third of patients who are diagnosed with breast cancer, the level of CEA in the blood is increased.
However, the increase in CEA (within the range of less than 10 ng / ml) can be observed in certain diseases of the gastrointestinal tract, liver or lungs not associated with oncology.
Breast cancer markers: HER2
And another analysis - on the receptor of human epidermal growth factor (HER2, Human Epidermal Growth Factor Receptor 2) - provides information on the presence of tyrosine protein kinase - a protein transmembrane cellular receptors that accelerate the growth and division of epithelial cells.
For the analysis, a tumor biopsy is done or a sample of its tissue is taken after surgery for the removal of the tumor. According to statistics, this protein is present in large numbers in 25-30% of cases of breast cancer. Also, the level of HER2 is increased in malignant diseases of the uterus, ovaries and stomach.
[16], [17], [18], [19], [20], [21]
Decoding of breast cancer markers
It should be noted that, according to the research, breast cancer markers, in particular CA 15-3, were raised in approximately 20% of patients with oncological breast tumors diagnosed in the first or second stages of the disease. Although in the later stages breast cancer markers are already raised in eight patients out of every ten.
Cancer antigen 15-3 (CA 15-3), cancer antigen 27-29 (CA 27-29), and carcinoembryonic antigen (CEA) when decoding breast cancer markers are detected in 50-90% of women with metastatic breast cancer.
Despite the radiographic signs of the persistence of the disease, the interpretation of the cancer markers of the breast cancer CA 15-3 can show an absolutely normal level (that is, within 30 U / ml), which means that the treatment was successful, and the residual tumor fixed on the mammogram is no longer viable.
If the breast cancer markers are increased - CA 15-3 above 30 U / ml, CA 27-29 above 40 U / ml - that is, there are good reasons to diagnose oncology. When the indicators do not decrease after treatment, there are two options: either the treatment was wrong, or the disease progresses.
If breast cancer markers increase after the therapy, then this is a clear sign of its inefficiency. In this case, the absence or presence of clinical improvements is taken into account.
So the interpretation of breast cancer markers withancer antigen helps to detect recurrences of the breast tumor after treatment, as well as metastases at earlier times.
Breast cancer markers HER2 show whether it is possible to use a drug such as Trastuzumab (Herceptin, Kadzila) that blocks the synthesis of the transmembrane cell receptor protein and stops the growth of cancer cells. In some cases, the results of this biological testing help oncologists assess the propensity of the tumor to progress, determine how the body responds to the treatment and determine the need for specific chemotherapy.
By the way, there are a little raised breast cancer markers in the last trimester of pregnancy, with liver cirrhosis, chronic hepatitis, systemic lupus erythematosus, sarcoidosis, tuberculosis. Therefore, to date, breast cancer markers are not an absolute indicator of oncology without the visualization of tumors with the help of mammography.