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August 10, 2017

Can a ‘liquid biopsy’ detect cancer and save lives?

  • Science
  • Genetics/Genomics

STAT – A blood test can detect DNA associated with nasopharyngeal cancer in seemingly healthy people, leading to earlier diagnosis and saving lives, researchers in Hong Kong reported on Wednesday in the New England Journal of Medicine.

Diagnosing tumors via a simple blood test has become a holy grail (a company developing such “liquid biopsies” is even named Grail). Much of the research is aimed at figuring out how to detect and analyze “circulating tumor DNA,” genetic material that’s released from dead cancer cells, something scientists first noticedin 1977. Circulating tumor DNA is rare compared to other DNA in the blood, however, so although there are intense efforts underway to detect ever-lower concentrations of it, the Hong Kong scientists looked for something else: DNA from Epstein-Barr, a virus that can cause nasopharyngeal cancer.

That improved their odds. Every nasopharyngeal tumor cell carries 50 copies of the Epstein-Barr genome, and the specific sequence the researchers fished out and amplified occurs about 10 times in every viral genome. That meant 500 targets per tumor cell, compared to one for the human DNA in most cancer cells.

Read more at STAT.

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