Platelets sequester cfDNA during circulation. Credit: Science (2025). DOI: 10.1126/science.adp3971

Swansea University has helped uncover a surprising new role for platelets—one that could significantly advance early cancer detection.

The study, led by the University of Oxford and published in Science, has revealed that platelets act as scavengers, capturing and storing fragments of DNA circulating in the blood, including mutated DNA in patients diagnosed with cancer.

When cells die, they release genetic material into the bloodstream, triggering unwanted immune responses or other health problems.

Until now, scientists have not fully understood how the body clears these potentially harmful molecules, but the team's research suggests that platelets actively absorb stray DNA, helping to clean the blood and maintain immune balance.

Analysis of platelet DNA via a simple blood test has been able to detect the presence of even pre-cancerous changes, paving the way for early and accurate cancer screening methods that are less invasive.

Professor Paul Rees from Swansea's Faculty of Science and Engineering, who co-supervised the project, played a key role in analyzing microscopy data that confirmed this process.

Professor Rees said, "The role of platelets, which are primarily involved with blood clotting, in absorbing cell-free DNA from the blood was completely unexpected. Also, the protection they give the internalized DNA from degradation in the blood means that this source of platelet DNA is perfect for detecting modifications and mutations that indicate diseases such as cancer in the body at a very early stage."

The analysis of circulating DNA in the blood is emerging as an important screening method in a number of health care settings. However, current approaches discard the platelets and only focus on platelet-depleted blood plasma.

Project lead author Dr. Lauren Murphy, a postdoctoral researcher from the MRC Weatherall Institute of Molecular Medicine (MRC WIMM), said, "Our study suggests that platelets might be even more important for our health than we previously realized. It also indicates that current liquid biopsy screening methods are overlooking valuable genetic information that is contained within platelets."

Remarkably, the team also discovered evidence of fetal DNA in the platelets of pregnant mothers, offering new possibilities to refine and improve genetic testing methods used today.

Dr. Bethan Psaila, Associate Professor of Hematology at the University of Oxford and senior author of the study, said, "Our discovery that platelets act as tiny DNA dust-busters in the blood was unexpected. One lucky consequence of this is that platelets bear hallmarks of DNA damage that has occurred in all tissues in our body—and analysis of platelets can potentially improve screening tests, including for cancer."

The study was a collaborative effort between researchers at Oxford, the University of Edinburgh, and Swansea University.

More information: Lauren Murphy et al, Platelets sequester extracellular DNA, capturing tumor-derived and free fetal DNA, Science (2025). DOI: 10.1126/science.adp3971  Journal information: Science