New blood test to detect more cancers
One study found that a new blood test could detect and localize more than 20 cancers with a high degree of accuracy. According to researchers, early detection of common cancers can result in many patients receiving more effective treatment.
As reported by the Dana-Farber Cancer Institute in Boston, Massachusetts, the test developed by GRAIL, Inc. uses Next Generation Sequencing (NGS) technology to study DNA for minor chemical labels (methylation) that affect whether genes are active or inactive.
Almost 3,600 blood samples were examined
Using nearly 3,600 blood samples – some from cancer patients, others from people who have not yet been diagnosed with blood sampling – a cancer signal from cancer specimens has been successfully detected and the cancer correctly detected in the originating tissue The specificity of the test – its ability to produce a positive result only when cancer was present – was great, as was its ability to localize the source or tissue.
New test requires DNA that can release cancer cells into the bloodstream when they die. Unlike "liquid biopsies", which detect genetic mutations or other changes in cancer associated with DNA, the technology focuses on DNA modifications known as methyl groups.
Methyl groups can be linked to DNA to control which genes are "on" and "off". Abnormal methylation patterns in many cases suggest more cancers and cancers than mutations. The new test looks at parts of the genome where abnormal patterns of methylation are found in cancer cells.
More effective treatment thanks to early diagnosis
"Our previous work has shown that methylation-based methods outperform conventional approaches to DNA sequencing to detect multiple cancers in blood samples," said lead author Dr Ing. Offiefrey Ocknard, of the Dana-Harber Cancer Institute, who is part of the Harvard Medical School in Boston. "The results of a new study show that such tests are a viable means of testing people for cancer."
In the study, researchers analyzed cell-free DNA in 3,583 blood samples, including 1,530 cancer patients and 2,053 non-cancer patients. Patient samples included more than 20 types of cancer, including breast, colon, esophageal, gall bladder, stomach, head and neck, lymphatic leukemia, multiple myeloma, lung, ovarian, and pancreas.
Overall specificity was 99.4%, which means that only 0.6% of the results falsely indicated the presence of cancer. The test found 76% of cases of high-mortality cancer. Within this group, the accuracy of the test for cancer patients was 32 percent; the second phase of 76 percent; at stage III at 85 percent and at stage IV at 93 percent.
If the test is widely used, recognizing a small percentage of common cancers can make many patients more effective, Ocknard said. (AD)
- Dana-Charber Cancer Institute: Discovering More Cancer Types, (Available at: 29.09.99), Dana-Charber Cancer Institute
This article contains general information only and should not be used for self-diagnosis or treatment. He could not replace a doctor's visit.