Wednesday, 19 December, 2018

DNA 'fingerprint' brings prospect of fast test for cancer

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Melissa Porter | 06 December, 2018, 03:09

Researchers have always been looking for a commonality among cancers to develop a diagnostic tool that could apply across all types.

Current detection of cancer requires a tissue biopsy - a surgical procedure to collect tissue from the patient's tumour.

If the water stays pink this would suggest you have cancer, although the test can not detect what type or how advanced the disease is.

"So we were very excited about an easy way of catching these circulating free cancer DNA signatures in blood", he said.

Now researchers have discovered that patterns of molecules attached to DNA, which control which genes are switched on and off, look different on cancer cells.

A normal cell DNA's distinct methyl pattern is crucial to regulating its machinery and maintaining its functions.

"Virtually every piece of cancerous DNA we examined had this highly predictable pattern", he explained. These were different to what we saw with normal tissue DNA in the water. Though made of gold, the particles turn the water pink. This is because gold can affect molecular behaviour in a way that causes visible colour changes.

Those specific structures can then be separated from the solution by sticking them to bare metal surfaces such as gold, the researchers found. "This could be done in conjunction with other tests and the combined information may give us a lot of ideas of where the cancer is and the stage".

The test also works for electrochemical detection - when the DNA is attached onto flat gold electrodes.

"This led to the creation of low-priced and portable detection devices that could eventually be used as a diagnostic tool, possibly with a mobile phone".

For this test to work properly the DNA must be pure. These signatures are gold-hungry, which makes them possible to identify with a simple color-change test. Trials are still in the initial stages and it has only been tested on breast, bowel, prostate, and lymphoma cancers but the researchers say it could have the ability to spot any type of cancer with up to 90 percent accuracy.

And though this "methylscape" could serve as a biomarker for cancer, researchers didn't have a good way to detect it.

It is based on a process known as epigenetics - the attachment of a chemical tag known as a methyl group to DNA.

It is a promising start, though further analysis with more samples is needed to prove its clinical use.

Although it is far too early to know how useful the discovery could be as a clinical tool, scientists said it was an exciting advance in the understanding of cancer.

We are also considering whether the test could help monitor treatment responses based on the abundance of DNA signatures in body fluid during treatment.

"You can detect it by eye - it's as simple as that", study senior author Matt Trau, a professor and senior group leader at the University of Queensland's Australian Institute for Bioengineering and Nanotechnology, said in a statement.

This article has been republished from materials provided by The University of Queensland.