New blood test capable of detect 20 types of cancers

A new blood test has shown ability to screen numerous types of cancer with a high degree of accuracy. A trial of the test showed it detected and localised more than 20 types of cancers. The test, developed by biotechnology company Grail Inc uses next-generation sequencing technology to probe DNA for tiny chemical tags (methylation) that influence whether genes are active or inactive.

When applied to nearly 3,600 blood samples-some from patients with cancer and some from people who had not been diagnosed with cancer at the time of the blood draw-the test successfully picked up a cancer signal from the cancer patient samples, and correctly identified the tissue from where the cancer began (the tissue of origin)," said investigators from Boston-based Dana-Farber Cancer Institute.

The test's specificity - its ability to return a positive result only when cancer is actually present - was high, as was its ability to pinpoint the organ or tissue of origin, they found. The new test looks for DNA, which cancer cells shed into the bloodstream when they die. In contrast to "liquid biopsies," which detect genetic mutations or other cancer-related alterations in DNA, the technology focuses on modifications to DNA known as methyl groups.