Scientists have developed a simple DNA test that can identify 18 early stage cancers which experts say could represent a medical “gamechanger”.
Cancer accounts for one in six deaths worldwide, but early detection can greatly improve outcomes. Existing screening tests have disadvantages including invasiveness, cost and low levels of accuracy for early stage disease.
Now US researchers have designed a test that analyzes proteins in the blood and can pick up 18 early stages cancersrepresenting all major organs in the human body.
Specific blood proteins could already be used for early detection and monitoring, but tests have so far lacked sensitivity – accuracy in picking up those with cancer – and specificity – accuracy in excluding those without cancer, the researchers said.
The team, from US biotech firm Novelna, said their test outperformed others that rely on tumor DNA in the blood, and had “a sensitivity far greater” than the Galleri test tested on the NHS in the UK become
By looking at proteins in blood plasma, the experts were able to distinguish cancer samples from normal ones, and even differentiate between different types of cancer “with high accuracy”. The research also found evidence that cancer protein signals were likely to be sex-specific.
The team wrote in the journal BMJ Oncology: “This finding is the basis for a multi-cancer screening test for the early detection of 18 solid tumors covering all the major human organs of origin for such cancers at the earliest stage of their development . with high accuracy.”
They added: “This could reshape screening guidelines, making this plasma test a standard part of routine screening.”
“These findings pave the way for a cost-effective, highly accurate, multi-cancer screening test that can be implemented on a population-wide scale.”
Blood plasma samples were collected from 440 people diagnosed with 18 different types of cancer, and from 44 healthy blood donors.
The team then identified proteins that showed early stage cancers and where they originated “with high precision” in the body.
The team wrote: “In stage I (the earliest cancer stage) and with the specificity of 99%, our panels could identify 93% of cancers among men and 84% of cancers among women.
“Our sex-specific localization panels consisted of 150 proteins and were able to identify the tissue of origin of most cancers in more than 80% of cases.”
Analysis of the plasma protein also showed that almost all were present at very low levels. This shows the importance of low-level proteins in picking up pre-cancerous and early-stage disease before a tumor has had time to cause significant damage, the team said.
However, the team said their relatively small sample size means further studies in larger groups of people are needed.
Dr. Mangesh Thorat, from the Center for Cancer Prevention at the Wolfson Institute for Preventive Medicine, which was not involved in the study, said questions remain about the test and more studies are needed.
“However, the interesting aspects of this test are a much higher sensitivity for stage I cancers than other similar tests in development and sex-specific performance differences that are biologically and clinically relevant,” he said.
“If the test performance in future, well-designed sequential studies is anything close to what this preliminary study suggests, then it could really be a game changer.”
Prof Paul Pharoah, a cancer epidemiology expert at Cedars-Sinai Medical Center, who was also not involved in the study, welcomed the findings but urged caution.
“Simple blood tests that can detect many different cancers in the early stages (test is sensitive) and do not generate false positives (test is specific) are a holy grail for early detection,” he said.
“This article reports on the initial results of the development of one such test. Although the results show some promise, it is far too soon to be sure that this test will be useful for early detection of cancer.”
