Tissue compatibility antigens – potential cancer markers?
Cancer can be diagnosed by a blood testAlla Solodova, Infox.ru
Sick cells feed and live differently from healthy neighbors.
And they should throw other products into the blood. According to these products, scientists proposed to diagnose oncological diseases.
More than eight thousand human proteins have been collected in the PRIDE, PeptideAtlas and Peptidome databases. Many of them are considered "garbage". Although, rummaging in such a "dumpster", you can find a lot of seemingly inconspicuous, but valuable molecules.
Garbage in the bloodBlood serum is the most suitable example of a "precious garbage dump" in which biomarkers of autoimmune, oncological and infectious diseases can be detected.
Moreover, it is not always possible to find the actual viral protein, which can serve as an indicator of inflammation. But in the blood there are always decay products of dying cells or specific compounds characteristic of the metabolism of unhealthy tissues. Small and few molecules are not always possible to detect in the free state. They are like dust, which is present on any surface, but becomes noticeable only if it is collected with a damp cloth.
In the body of animals, there are also such "rags" – sHLA (soluble human leucocyte antigens) molecules that enter the blood from the cell. Actually, human leukocyte antigens (HLA), they are also tissue compatibility antigens, are located on each cell membrane. They are similar to antennae and are involved in the recognition of foreign cells. The polypeptide composition of HLA molecules depends on which proteins are present inside the cell outside of which the molecule is located. If the cell's metabolism is changed, it synthesizes "painful" compounds, and they immediately appear on the surface of the membrane, and after some of them – sHLA – in plasma. In this sense, sHLA is the very "rag" that collects "dust" inside the cell and throws it into the blood.
Previously, scientists proposed using antigens sitting on cell membranes to identify the features of the metabolism of cancer cells. At the same time, many researchers have noted that with allergic reactions, autoimmune, viral and oncological diseases, the number of specific sHLA in the blood increases. It is clear that the more cells are sick, the higher the concentration of unusual sHLA. Therefore, scientists have proposed using the sHLA level as a marker for an unfavorable prognosis of the disease.
Not garbage, but a biomarkerIsraeli scientists led by Michal Bassani Sternberg from the Technion–Israel Institute of Technology (Techion-Israel Institute of Technology) proposed and tested a fundamentally new approach to the use of sHLA molecules.
The authors of the methodology believe that specific proteins can not only predict an unfavorable outcome of the disease, but also diagnose oncological diseases. However, for this it is necessary to compile a complete database of proteins that enter the blood from diseased cells.
Michel Bassani-Sternberg conducted a pilot study on the blood of patients with multiple myeloma, acute myeloid leukemia and acute lymphoblastic leukemia. The scientists described the sHLA profile of each of the patients, and then compared it with the sHLA profile of healthy people. They also compared with the obtained data an HLA portrait of blood and diseased cells cultured in vitro.
As a result, the researchers were able to identify and study more than 12,000 sHLA. It turned out that cancer cells secrete much more sHLA than healthy cells of the same type. Moreover, the amount of sHLA in the blood of healthy people turned out to be very small. Scientists note that the more aggressive and neglected the disease was, the more similarities there were between HLA located in blood plasma and on the surface of cells.
According to the results of the study, the authors were able to identify some specific sHLA that can be used to diagnose leukemia and myeloma. In the article Soluble plasma HLA peptidome as a potential source for cancer biomarkers, scientists write that for the practical application of the proposed diagnosis, it is necessary to compile a database of sHLA.
Portal "Eternal youth" http://vechnayamolodost.ru28.10.2010