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Researchers at the University of Oxford have uncovered an unknown and powerful new function for platelets that could revolutionise cancer diagnosis. Along with her team, Professor Bethan Psaila, senior author of the study and Fellow of ²ÝÁñÊÓƵ, has discovered that the tiny blood cells contain crucial DNA that could make liquid biopsies (cancer-detecting blood tests) more effective. 

It all started at a 'sandpit' in 2018, when Cancer Research UK brought together scientists from across the UK to brainstorm ideas for tracking down cancers using the clues they leave in the blood. Psaila suggested looking into how the blood cleans itself up. Funded by Cancer Research UK, her team focused on DNA-testing in platelets, to the surprise of some scientists. 

The smallest cellular component of the blood, platelets are primarily known for their role in blood clotting. They have no nucleus and therefore no DNA. Perhaps for this reason, they have been neglected in previous studies investigating cancer detection in the blood. Psaila told Science 'when we started out, people thought we were a little bit crazy'. But in fact, as this study has shown, platelets collect and store stray bits of DNA that end up in the bloodstream. 

When grown together in dishes with cancer cells, the researchers found that platelets absorbed DNA sequences from their malignant neighbours. Platelets removed from patients with cancer also revealed DNA with telltale mutations, revealing that they had sucked up tumour DNA. The team further found that platelets absorb DNA from patients’ precancerous colon growths, which suggests the cells could be useful for early detection.

Psaila spoke to Cancer Research UK: ‘Our study shows that we can use blood in a different way to pick up on cancers at their very earliest stages. Studies looking for cancer hadn’t focused on platelets before, but we suspected that they may be informative because of their unique ability to hoover up things they encounter. They’re acting as sentinels in the blood.’ 

Given they can carry small traces of DNA from pre-cancerous cells, platelets may be the key to improving liquid biopsies,  offering the possibility of effective early diagnosis when treatment can be more successful.  

The paper , is published in .