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Health and Medicine

New Blood Test Detects Eight Different Cancers By Hunting Down Their DNA

author

Rachel Baxter

Copy Editor & Staff Writer

clockNov 8 2018, 13:03 UTC

opard wattanasakul/Shutterstock

Detecting cancer is a tricky business. It can involve unpleasant procedures like mammograms and colonoscopies and often tumors are only detected once they’ve reached a certain size. Scientists are working to find better alternatives, like simple blood tests, that are less invasive and detect cancer earlier, making it more treatable.

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Now, researchers from Cancer Research UK’s Cambridge Institute have developed a blood test – or “liquid biopsy” – that can detect eight different kinds of cancer, including breast, ovarian, skin, and brain cancer. While other cancer blood tests have also been developed, this one is relatively quick, as it doesn’t involve the same lengthy genetic sequencing of the patient’s blood.

Instead, the new test works by tracking down cancerous DNA that’s circulating in the bloodstream based on its size. Tracing a tumor’s DNA is usually very difficult as it's hugely outnumbered by healthy DNA within the body. To combat this problem, the researchers identified key differences between the sizes of DNA fragments from tumors and healthy tissue, and used these differences to pick out the cancerous DNA. Their findings are published in the journal Science Translational Medicine

The team then conducted an experiment to see how effective their method was at determining whether someone had cancer. Their test managed to detect colorectal, bile duct, ovarian, breast, and skin cancer in 94 percent of 68 patients tested. A slightly lower success rate was achieved for pancreatic, kidney, and brain cancers, with 65 percent of the cancer being detected in 57 patients.

The new test isn’t perfect, it gave a false positive – meaning that it wrongly detected cancer in a healthy patient – 2.5 percent of the time.

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"A limitation at the moment is that we demonstrate the potential in late-stage patients, but not yet with samples collected from patients at an earlier stage of the disease," lead author Florent Mouliere told IFLScience.

Nevertheless, the liquid biopsy is certainly promising, and, as Mouliere told New Scientist, the blood test could easily be carried out by commercial labs meaning that real-life application might not be too far away.

"More than a test, our work is the description of a new method, or approach, that could be applied to other sequencing methods, or future methodologies," Mouliere told IFLScience. 

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The same research group recently published another paper detailing how they managed to use liquid biopsies of cerebrospinal fluid to spot brain tumors. If one day used in a clinical setting, this technique could reduce the need for tissue biopsies, a risky procedure when the tumor is situated in the brain.  

[H/T: New Scientist]


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