22 February 2016
Blood Test Could Detect Five Key Cancers at Early Stage
A simple blood test currently being developed by scientists in the United States could detect five key cancers at an early stage, meaning thousands of lives could potentially be saved by early treatment.
Researchers at the US National Human Genome Research Institute (NHGRI) have identified a particular gene unique to tumour DNA that changes its chemical ‘signature’ when breast, lung, bowel, womb and stomach cancer is present in the body.
Scientists believe this change could occur when the body begins to lose its fight against the disease and that the signature may be present in many more types of cancer.
The tell-tale signature in question is linked to a gene known as ‘ZNF154’. When cancerous tumours from 13 different organs were analysed in 2013 it was found that in every case where a tumour was present, the gene showed increased signs of methylation.
Methylation is a biochemical process akin to a dimmer switch which tells genes to either decrease gene activity or in effect, switch to the ‘off’ position.
The current NHGRI study examined the possibility of using the enhanced methylation as a reliable indicator of cancer. Researchers compared 184 tissue samples from breast, lung, bowel, womb and stomach tumours with 34 healthy tissue samples in an effort to study ways to identify tumour DNA and distinguish it from healthy cellular DNA.
Dr Laura Elnitski, whose research group led the study, said: “Finding a distinctive methylation-based signature is like looking for a spruce tree in a pine forest.
"It's a technical challenge to identify, but we found an elevated methylation signature around the gene known as ZNF154 that is unique to tumours."
Crucially, the research group discovered that the genetic change was consistent across all five key cancers, suggesting that it could be used as a universal cancer marker.
The study also revealed that the enhanced methylation was detectable even at limited concentrations in the blood, indicating that a simple blood test could potentially be used to identify tumours at an early stage.
At present, diagnostic tools for cancer involve tests and procedures such as, mammograms, colonoscopies and biopsies. Blood tests in turn, need to be specific to a known tumour type and doctors must first suspect that cancer is present.
It is hoped that the new blood test, which does not need any prior knowledge of the cancer, will not only be less invasive but, more easily able to detect early-stage cancer when treatment is more effective. It could also be used to monitor patients deemed at particularly high risk of cancer as well as tumour behaviour during treatment.
The earlier cancer is diagnosed and treated, the better the chances of recovery. More than 70,000 people die every year in the UK from the five cancers this blood test is able to detect. The majority of these deaths occur because tumours are not identified early enough.
Paul Sankey is a senior medical negligence solicitor at Slater and Gordon Lawyers in London.
Slater and Gordon help people who have suffered from delayed or wrong diagnosis of cancer due to medical negligence.
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