Is a universal cancer test possible?
Research published in Nature Communications suggests that it might be.
Scientists, based at the University of Queensland, have discovered something they believe to be common to all cancers – a unique nano-scaled DNA signature.
The scientists used this unique signature to develop a test that might detect cancer from any tissue type, including blood.
Dr Laura Carrascosa, a researcher at the University of Queensland, said: “There’s been a big hunt to find whether there is some distinct DNA signature that is just in the cancer and not in the rest of the body.”
To find this distinct signature the researchers assessed molecular patterns displayed by methyl groups that are usually distributed evenly across a healthy cell’s DNA. Methyl groups serve as signals to control which genes are turned on or off at any given time and are very important to cell function.
The team discovered that in a cancer cell the genome is almost bare, except for intense clusters of methyl groups at specific locations.
This signature, named by the scientists as the cancer ‘methylscape’ appeared in breast, prostate and colorectal cancer cells.
“Virtually every piece of cancerous DNA we examined had this highly predictable pattern,” said Professor Matt Trau, lead researcher at the University of Queensland.
It was then found that these clusters of methyl groups cause cancer DNA fragments to fold into 3-D structures that will stick to gold nanoparticles.
The researchers made use of this curious finding to develop the reported cancer detection method. They used gold nanoparticles that change colour depending on whether the 3D nanostructures associated with cancer DNA are present or not. The resulting test is simple, cheap and can provide results in less than 10 minutes and is believed to potentially be a radical new approach to cancer detection.
“Our technique could be a screening tool to inform clinicians that a patient may have a cancer, but they would require subsequent tests with other techniques to identify the cancer type and stage,” Carrascosa said.
The test has been reported to have a sensitivity of around 90%, so would detect 90 in 100 cases of cancer.
Dr Ged Brady, of the Cancer Research UK Manchester Institute, commented: “This approach represents an exciting step forward in detecting tumour DNA in blood samples and opens up the possibility of a generalised blood-based test to detect cancer. Further clinical studies are required to evaluate the full clinic potential of the method.”
Gene-edited babies – how far is too far?
Claims by scientist He Jiankui last month of the creation of the world’s first gene-edited twins, shocked and appalled the global scientific community.
His experiment still hasn’t been fully substantiated, but the way it was conducted, the implications of his research and the way it was announced, has caused worldwide controversy.
“We heard an unexpected and deeply disturbing claim that human embryos had been edited and implanted, resulting in a pregnancy and the birth of twins,” read a statement released by the organising committee of the Second International Summit on Human Genome Editing in Hong Kong.
“Even if the modifications are verified, the procedure was irresponsible and failed to conform with international norms.”
He Jiankui is an associate professor at the Southern University of Science and Technology in Shenzhen, an institution that denied any knowledge of his research.
Xu Nanping, Vice-Minister for Science and Technology told the Chinese state-owned network CCTV: “The genetically edited infant incident reported by media blatantly violated China’s relevant laws and regulations. It has also violated the ethical bottom line that the academic community adheres to. It is shocking and unacceptable.”
CRISPR is a gene-editing tool, that can be used to control which genes are expressed in an organism. Through its use, it’s possible to delete undesirable traits or add them to an organism’s genome.
It has previously been used in the lab for editing human embryos, but the created embryos have never been implanted and allowed to develop into gene-edited babies. The novel nature of this procedure, the lack of testing and disregard of the proper protocol has raised concerns with many in the science community.
Were the parents properly informed of what was happening? Did they understand the implications fully? Could the technology have unwanted side effects? Is it ethical? These are just a few of the questions currently circulating.
The edited embryos also have germline mutations, meaning that the edited genes of the twins could be passed on to any children that they may have.
The creation of the CRISPR edited twins has shown the potential threat and power of technology that isn’t carefully regulated and monitored. And it serves as a call to action for scientists and regulators across the globe to think more carefully about gene editing technology.
But is the answer simply to suspend gene-editing efforts? Or could this create even more problems with scientists going underground to try out this new tech?
Written by Angharad Baldwin