Annals of Oncology: "Research" Blood Test can detect a wide range of cancers that can be used in high-risk populations in clinical studies

A new blood test involving the upper hand detected more than 50 types of cancer, as well as their lesions in the body, with particularly high accuracy, according to an international team of researchers led by the Dana-Farber Cancer Institute and the Mayo Clinicstudy, published online March 30, 2020 in the Annals of Oncology, shows that the blood test can play a crucial role in early cancer testingIt can identify particularly dangerous cancers that lack standard screening methodsthe test, developed by GRAIL in Menlo Park, California, uses next-generation sequencing techniques to analyze the arrangement of chemical units called methyl snares in cancer cell DNAMethyl groups attach to specific parts of DNA, helping to control gene activity and inactivityThe position or methylation pattern of the methyl group is significantly different in cancer cells and in normal cellsTo some extent, abnormal methylation patterns are more characteristic of cancer cells than genetic variantsWhen cancer cells die, their DNA adheres to the meth and flows into the bloodstream, where it can be analyzed with new tests" Our previous work has shown that methylation-based testing is superior to traditional DNA sequencing methods in detecting multiple cancers in blood samples," said DrJeffrey Oxnard, M.D., of the Dana-Farber Institute, and DrMinetta Liu of the Mayo Clinic"The results of this study suggest that these tests are feasible methods for detecting a wide range of cancer patients, the test was developed by GRAIL to detect tiny chemical markers (methylation) in DNA using next-generation sequencing techniques that affect gene activity or inactivityWhen applied to nearly 3600 blood samplesSome are samples of cancer patientsSome are blood samples that were not diagnosed with cancer when they were pumped The test successfully selected cancer signals from blood samples from cancer patients and accurately identified tissue changes in the early stages of cancer The researchers found that the specificity of the test -- the ability to have positive results only if cancer is present -- was high, and that it could accurately locate the source of organs or tissues the new test looked for DNA that enters the blood stream when cancer cells die Unlike "liquid living tissue tests" that detect genetic mutations or other cancer-related DNA changes, the technique focuses on changes in DNA called methyl Methyl can be attached to a chemical unit of DNA, a process known as methylation to control which genes are "on" and which are "off" In many cases, the abnormal pattern of methylation is more indicative of cancer and type of cancer than mutations The new test targets parts of the genome that find abnormal methylation patterns in cancer cells the study, the researchers analyzed 6,689 blood samples of free DNA (the DNA of normal cells and cancer cells that enter the blood at the time of cell death) including 2,482 blood samples from cancer patients and 4,207 blood samples from non-cancer patients There are more than 50 types of cancer in the blood samples of cancer patients, including breast cancer, colorectal cancer, esophageal cancer, gallbladder cancer, bladder cancer, stomach cancer, ovarian cancer, head and neck tumors, lung cancer, lymphatic leukemia, multiple myeloma, pancreatic cancer, etc overall, the accuracy of the tests was as high as 99.3 per cent, meaning that only 0.7 per cent of the results of identifying cancers were wrong Twelve cancers account for 67.3 percent of the results of nearly two-thirds of Cancer Deaths in the United States, meaning that the test can detect cancer two-thirds of the time, but one-third of the time it turns negative In this group, the sensitivity of stage I cancer patients was 39%, in stage II patients was 69%, in stage III patients was 83%, and for stage IV patients was 92% Phase I-III sensitivity for all 50 cancer types was 43.9% When cancer is detected, the test accurately identifies organs and tissues of the origin of cancer in more than 90 percent of cases This is key information to determine how to diagnose and manage the disease "Our results suggest that this method of detecting the DNA of free cells in the blood can detect a wide range of cancer types at almost any stage of the disease, and that their specificity and sensitivity are close to the national screening level," Oxnard said.
"This test could be an important part of early cancer detection clinical trials If the test is widely used, even a small percentage of common cancers detected early may lead to more effective treatment for many patients, Oxnard said