DNA of lymphocytes will help in the diagnosis of cancer
The British have proposed a new blood test for cancer
The test allows not only to detect certain types of cancer at a very early stage and identify people at risk, but also eliminates the need for such an invasive procedure as a biopsy. The work is published in the October issue of The FASEB Journal: Anderson et al., Sensitivity and specificity of the empirical lymphocyte genome sensitivity (LGS) assay: implications for improving cancer diagnostics.
The test for "lymphocyte genome sensitivity" (lymphocyte genome sensitivity, LGS) is based on a well-known method for detecting damage to cellular DNA, the so-called "comet DNA assay" (comet assay). In this case, white blood cells and lymphocytes are being studied. The cells are placed in a layer of agar-agar deposited on a slide and subjected to harsh ultraviolet radiation damaging the genetic material. As a result of the damage, DNA fragments unrelated to the cell are formed, which are pulled in an electric field in the agar-agar layer towards the anode. At the same time, the observed objects form a "tail", making them look like comets. By the number and length of such "tails", the degree of DNA damage is judged.
The authors slightly modified the method by varying the thickness of the agar-agar layer and the radiation intensity. It was found that in healthy people, with an increase in the layer, the level of damaged DNA returns to normal, while in cancer patients it remains high. In the case of a precancerous condition, the results are intermediate. This gradation reflects the degree of vulnerability of cellular DNA, which becomes maximum in cancer.
The LGS test was tested on blood samples from 208 people. 20 of them were diagnosed with melanoma, 34 with colon cancer, four with lung cancer, 56 people were in precancerous condition, 94 were healthy. The test showed a very high level of sensitivity and specificity, which, as the authors note, with some optimization can be brought to 100 percent. Such a test can be used for cancer screening both by itself and in combination with other diagnostic methods.
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