PARIS (AFP) - Scientists said Wednesday they had identified a marker in blood for pancreatic cancer, raising hopes for a test that would allow earlier diagnosis of this deadly disease.
A research team from the United States and Europe said people with cancer of the pancreas had a protein called glypican-1 (GPC1) in their blood.
The protein is contained in exosomes - tiny bags containing genetic information in the form of DNA and RNA which are excreted by all types of cells.
Exosomes from healthy cells were not found to contain GPC1.
Having found the marker in mice, the team took blood samples from humans, and found GPC1 in the blood of all 250 pancreatic cancer patients they tested, according to study results published in the journal Nature.
They were able to distinguish between the blood of cancer sufferers and 120 healthy volunteers - "a highly reliable biomarker," study co-author Raghu Kalluri of the University of Texas' MD Anderson Cancer Centre told AFP.
There were no false positives or false negatives, the team said.
And the test showed higher levels of the protein in people who were more severely ill, suggesting it could also be used to monitor disease progression.
Pancreatic cancer has a poor survival prognosis, largely because it often goes undetected for long, giving it time to spread.
Steve Jobs, who helped build Apple into one of the world's most recognisable brands, died in 2011, aged 56, after battling pancreatic cancer.
Actor Patrick Swayze died in 2009, aged 57, after a 20-month fight with the disease.
According to the International Agency for Research on Cancer, pancreatic cancer was responsible for about 3.7 per cent (173,827) of cancer deaths in 2012, and 2.4 per cent (178,161) of total cancer cases.
The discovery may raise hopes for an earlier detection method in future - before standard imaging and tissue analysis can pick up the tell-tale signs of pancreatic cancer.
But while outsiders described the findings as exciting, they cautioned that further research is needed to confirm the result.
"The GPC1-positive exosomes were shown to be present in symptomatic patients, but there is no evidence that the GPC1-positive exosomes would be present before symptoms develop," Paul Pharoah, a cancer epidemiology professor at the University of Cambridge said in comments carried by Britain's Science Media Centre.
Added Alastair Watson of the University of East Anglia, the new test "is very complex to perform and many routine diagnostic labs will not have the equipment required."