Blood platelets do more than prevent bleeding. New research from Ludwig Cancer Research and the University of Oxford, published in Science, shows that platelets suppress inflammation and act as sensitive carriers of cancer and fetal DNA in the blood.
Usually recognized for their clotting role, platelets are small, nucleus-free cells. The study reveals that they absorb fragments of cell-free DNA (cfDNA) shed by dying cells. By doing so, they prevent harmful DNA buildup that can fuel autoimmune disorders. Conventional methods discard platelets before analyzing cfDNA in plasma, possibly missing crucial signals for disease detection.
Led by Bethan Psaila and Lauren Murphy, the researchers combined imaging, sequencing, and PCR analysis across dozens of patient samples. They found tumor and fetal DNA inside platelets, including Y chromosome fragments in healthy pregnant women. Patients with fewer platelets had higher cfDNA levels in plasma, confirming platelets’ role as genetic cleaners.
“While platelets do not have their own nuclei, we discovered that they act like sponges, mopping up the fragments of DNA that are released by dead and dying cells,” said Psaila.
Key Findings
- Platelets absorb cfDNA fragments released by dying cells, reducing harmful buildup.
- DNA from tumors and fetuses was detected inside platelets, including Y chromosome fragments in pregnant women.
- Patients with lower platelet counts showed higher cfDNA levels in plasma.
- Platelet-derived DNA could strengthen liquid biopsy for early cancer detection and prenatal screening.
- Findings provide new insight into thrombocytopenia and its link to inflammation.
The implications extend widely. Platelets may serve as biosensors for genetic activity across tissues, offering insight into cfDNA biology and its diagnostic promise. As millions worldwide undergo screening for cancer and genetic disorders, this overlooked platelet function could open the door to earlier and more precise diagnoses, improving health outcomes.
Science, August 14, 2025, DOI: 10.1126/science.adp3971
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