A nanoscale DNA signature that appears to be common to all cancers has been discovered and incorporated into a novel assay that enables cancer to be quickly and easily detected from any tissue type, according to researchers from the University of Queensland's Australian Institute for Bioengineering and Nanotechnology (AIBN).
Their research, which was published today in Nature Communications, reveals new insights about how epigenetic reprogramming in cancer regulates the physical and chemical properties of DNA and could lead to an entirely new approach to point-of-care diagnostics.
"Because cancer is an extremely complicated and variable disease, it has been difficult to find a simple signature common to all cancers, yet distinct from healthy cells," explains Dr Abu Sina.
Sina and the team examined epigenetic patterns on the genomes of cancer cells and healthy cells. These methyl groups are important to cell function because they serve as signals that control which genes are turned on and off at any given time. In healthy cells, these methyl groups are spread out across the genome. However, the AIBN team discovered that the genome of a cancer cell is essentially barren except for intense clusters of methyl groups at very specific locations.
This unique signature—which they dubbed the cancer "methylscape", appeared in every type of breast cancer they examined and appeared in other forms of cancer, too, including prostate cancer, colorectal cancer, and lymphoma. "Virtually every piece of cancerous DNA we examined had this highly predictable pattern," says Professor Matt Trau.
They also discovered that, when placed in solution, those intense clusters of methyl groups cause cancer DNA fragments to fold up into three-dimensional nanostructures that stick to gold. Taking advantage of this, the researchers designed an assay that uses gold nanoparticles that instantly change color depending on whether or not these 3D nanostructures of cancer DNA are present.
The technology has also been adapted for electrochemical systems, which allows inexpensive and portable detection that could eventually be performed using a mobile phone. So far they've tested the new technology on 200 samples across different types of human cancers, and healthy cells. In some cases, the accuracy of cancer detection runs as high as 90%.
"It works for tissue-derived genomic DNA and blood-derived circulating free DNA," says Sina. "This new discovery could be a game-changer in the field of point of care cancer diagnostics." It's not perfect yet, but it's a promising start and will only get better with time, says the team.