Release date: 2017-08-14
Scientists have the first important evidence of a liquid biopsy that helps screen cancer patients. Many of these studies are working to detect and analyze "circulating tumor DNA" (ctDNA), and many companies are working to develop these alternative versions for screening, such as mammography, colonoscopy, and the like. But ctDNA is so rare in the blood. So Hong Kong researchers turned their attention to the DNA of Epstein-Barr, which causes nasopharyngeal carcinoma, and tried it in nasopharyngeal cancer screening to improve the early detection and survival rate of the disease. New research suggests that this method is at least effective for this type of cancer that is prevalent in the area.
This is due to the fact that each nasopharyngeal carcinoma tumor cell carries 50 copies of the Epstein-Barr genome, and the investigator's target sequence undergoes about 10 amplifications per viral genome. This means that in each tumor cell, the target is 500 times that of human DNA.
Professor Dennis Lo of the Chinese University of Hong Kong said: "This work is very exciting on a larger scale because it provides a blueprint for testing other tumor types, such as the lungs or breast." The study was published in the New England Journal of Medicine NEJM on August 10. Professor Lu’s most famous discovery is the discovery of fetal DNA in the mother’s blood, which provides a new era of non-invasive testing for pregnant women.
Screening of 20,000 people has confirmed that 34 people have lived for 3 years.
The study involved nasopharyngeal carcinoma, which formed on the top of the throat behind the nose. This is a good DNA screening test because it is an invasive cancer, and early detection is very important and can be screened in the most common middle-aged male population of cancer. Moreover, the Epstein-Barr virus exists in most cases, so the test can look for a large amount of viral DNA that enters the bloodstream from the tumor, not the cancer cells themselves.
The general situation of the screening
Of the approximately 20,000 men screened, 1112 or 5.5% found viral DNA. Of these, 309 people conducted a confirmatory test one month later. After endoscopy and MRI, 34 people were confirmed to have cancer. Sixteen of the 34 cancers are very early, and the cancer does not have any symptoms at an early stage. Three years later, all patients except one patient survived and showed no signs of cancer after receiving standard radiation therapy. In contrast, only 70% of nasopharyngeal cancer patients usually survive for at least some time.
This test effectively improves survival in the early stages of nasopharyngeal carcinoma
In the early stages of nasopharyngeal carcinoma, more cases were found: 71% of the samples in stage I and stage II of nasopharyngeal carcinoma were found to contain viral DNA, and only 20 of the control groups treated for nasopharyngeal cancer in the past five years. %. This is important because early cases usually use only radiation therapy, but advanced patients require chemotherapy and treatment is less successful.
Screening also appeared to improve the 3-year progression-free survival rate of 97% in the 3-year period and 70% in the control group. Only one person with negative screening had nasopharyngeal cancer within one year.
Changes in the distribution and survival rate of nasopharyngeal carcinoma
The researchers estimate that screening a 593 person for a cancer case would cost $28,600. It is worthwhile in Hong Kong. Nasopharyngeal carcinoma is more common in South China, with as many as 35 cases per 100,000 people. But in other places where the disease is rare, more people will need to be screened, and the cost of finding each cancer case will be even greater. Dr. Richard Ambinder of the Johns Hopkins School of Medicine in the United States wrote a comment to the magazine. He said: "Despite this, this shows that there is great hope for liquid biopsy. This is an improvement that can indeed save lives."
Paper download
Analysis of Plasma Epstein–Barr Virus DNA to Screen
For Nasopharyngeal Cancer paper.pdf
Source: Bio-Exploration (micro-signal biodiscover)
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