These distinct patterns of molecules control which genes are turned on and off at any given time and "decorate the DNA".
Like this story? Subscribe to FierceBiotech! While the DNA inside normal cells has methyl groups dotted all over it, the DNA inside cancer cells is largely bare, with methyl groups found only in small clusters at specific locations.
Much more research needs to be done before that test can be widely used, the U.S. researchers added. This feature appears to be common to cancer DNA in general, regardless of the type of cancer, the researchers said.
The researchers have tested their technology on about 200 samples from cancer patients and healthy people, finding that the test was up to 90 percent accurate in detecting cancer.
The test, which has been performed with 90% accuracy on 200 samples of different types of cancers and healthy cells, is now at experimental stage and results require further validation through clinical trials before it can be made commercially available.
Physicians believe that their method can be used to test for cancer using a mobile phone.
Scientists worldwide have been working on ways to identify cancer earlier, as early detection is known to increase the success rate of therapeutic treatment and surgery.
The Guardian reported: "The test has a sensitivity of about 90%, meaning it would detect about 90 in 100 cases of cancer". When they die, they often burst, which releases everything inside those cells, including DNA.
"So we were very excited about an easy way of catching these circulating free cancer DNA signatures in blood", he said.
One question posed by Di Carlo: Do results depend on how much DNA is added - especially since cancer cells have more DNA?
"This led to the creation of cheap and portable detection devices that could eventually be used as a diagnostic tool, possibly with a mobile phone", Matt Trau, lead researcher of the study, said.
This led the team to develop a test that can make the difference between healthy and malignant cells. But if the technique is further developed, perhaps the most immediate potential application would be monitoring existing cancer patients for disease recurrence, she said. In contrast, normal DNA folds in a somewhat different way, which does not result in such a strong affinity for gold, the researchers said.
"We certainly don't know yet whether it's the holy grail for all cancer diagnostics, but it looks really interesting", he concluded.