A blood test for 50 types of cancer

In the case of cancer, it is crucial that, as early tumors are detected. This is because the earlier the stage, the lower the risk that the cancer has spread to other tissues. In the ideal case, the surgical removal of the tumor is sufficient at a very early stage Cancers, sometimes even without a burdensome chemotherapy is necessary. Accordingly, the efforts of the medical, meaningful early detection methods, and to develop. In the case of some types of cancer such as colon cancer or breast cancer, procedures such as mammography or colonoscopy, are used. However, for many other types of cancer, the appropriate Tests are missing yet. Among other things, that is why scientists have been looking for some time for a possibility of cancer through blood to identify tests. This is based on the recognition that there are some biomarkers and even free in the blood circulating cancer cells, which can show a tumor disease.

search for characteristic DNA retention

As a particularly promising approach to Tests, and not looking for typical DNA sequences of abnormal cells are, but according to epigenetic changes. These are small chemical groups called methyl groups that sit at different Points in the genome. Where these deposits are located, cannot be read at this point, the underlying genes are switched off in order quasi. This facility will be removed increases, the switch on this previously blocked genes. Such epigenetic changes can activate, for example, tumor genes, or control genes against degeneration off. Several groups of researchers are working on blood tests to prove such epigenetic markers in different types of cancer. First studies, there were, among other things, a Test of the cancer of the breast, prostate and colon cancer as well as lymphoma could see.

Now, researchers at the Circulating Cell-free Genome Atlas (CCGA)-consortium under the leadership of Michael silk, of US Oncology Research, have developed this test procedure. For that, they created an Assay of the methyl group with retention of more than one million Places in the DNA sensing. The evaluation of this data then takes an adaptive algorithm that has been trained to recognize the characteristic methylation patterns of 50 different types of cancer. In the Training, the blood served samples of 1531 patients with cancer and 1521 healthy control subjects as a practice material. The actual study carried out the scientists then with the blood samples from 1264 participants. “To our knowledge, this is the most comprehensive clinical genomics program, in which a blood test for the early detection of numerous cancer types and validated, it was developed,” says Seiden and his Team.

the match rate between the ages of 18 and 93 percent

The study showed that The blood test was in the majority of cases, successfully to distinguish cancer patients from healthy participants and could, in addition, define the type of cancer with high specificity, the researchers report. Accordingly, the Rate of false-positive results was only 0.7 per cent in the case of mammography-series of screenings for breast cancer can reach up to ten percent. Significantly lower the rate of successfully tracked the tumor was in the blood test, but disorders. Depending on the stage the margin was enough for all 50 types of cancer, which average only 18 per cent in the case of very early tumors in stage I, up to 93 per cent in the case of advanced cancer (stage IV). All the stages of the hit rate was 43.9 percent. Slightly better results were when the System was looking only diseases according to the twelve most common types of cancer, including stomach cancer, colon cancer, lung cancer, liver cancer, and pancreatic cancer, and leukemia. For these types of cancer is the blood test achieved a detection rate of 67.3 per cent, on all the stages averaged.

in addition to the recognition, whether the Patient is suffering a cancer or not, were able to determine the blood test and the analysis algorithm, in which the tissue or Organ of the malignant cells. This was achieved in 96% of the positive samples tested. The error rate was around seven percent. Taken together, these results support silk says the ability of this methylation tests to meet the basic requirements of a multiple-cancer-early-detection-blood-test”,. The detection of numerous types of cancer, with only one Test and low false positive Rate is one, but also the ability to indicate where in the body the cancer of the seats. Similarly positive is also the editor-in-chief of the magazine Annals of Oncology, the study has now been published, sees it: “This is an important study and a first step towards the development of easy-to-use Screening plant,” comments Fabrice André. “The early detection of more than 50 percent of the cancer cases could save millions of lives each year worldwide.” Whether the epigenetic Tests are useful but, in fact, to detect tumors at an early enough stage, we need further studies yet. To such a blood test can come out on the market, it will take some time.

source: Circulating Cell-free Genome Atlas (CCGA)-Consortium; Annals of Oncology, doi: 10.1016/j annonc.2020.02.011

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