March 5, 2025

expert reaction to study suggesting Aspirin may enhance the immune response against cancer metastasis in mice

A study published in Nature suggests that Asprin enhances the immune response against cancer metastasis in mice. 

Dr Harvey Roweth, a cancer biologist at the University of Reading, said:

“I don’t think we can say that cancer patients should be taking aspirin – at least, not yet.

“Aspirin is a very accessible drug, with relatively few side effects. This study in mice suggests we should further assess a role for aspirin in human metastatic cancer. It is worth noting that prior clinical studies that tested aspirin as a tool in fighting metastasis in human patients have been conflicting and often inconclusive. There are even some reports that conclude that aspirin may do more harm than good.”

“The mouse models don’t capture the full complexity of metastatic disease. Plus, in this study, the mouse models used predominantly look at melanoma cells that metastasises to the lungs. So, the paper doesn’t account for different cancers and spread to other organs.

“As a cancer biologist, the finding that is most exciting to me is that aspirin can preserve T-cell immune responses in an animal model.

“What we need now – and I strongly agree with the authors on this – are new randomised controlled trials that focus on finding biomarkers of the patient’s immune response. This is how we will find out which cancers and which patients are most likely to benefit from aspirin.

“It will also be important to consider that aspirin can be unsafe for certain individual patients. It can cause disruption of the stomach lining and increase the risk of bleeding in the gut. The study does not account for such side effects.

“There is some promise that aspirin will help patients in the future. It will need to be considered alongside existing therapies – aspirin is extremely unlikely to become a stand-alone treatment for cancers.”

Prof Mangesh Thorat, Honorary Reader, Queen Mary University of London & Consultant Breast Surgeon (Locum), Homerton University Hospital, London, said:

“We have known for a while that the beneficial effect of aspirin in preventing deaths from certain cancers is greater in magnitude than its effect in preventing development of these cancers. This can only happen if aspirin prevented or abrogated metastases from such cancers. Although it was thought to be mediated through the anti-platelet role of aspirin, the exact mechanism remained elusive. This elegant study in mice sheds light on how aspirin’s anti-platelet action reverses the suppression of certain immune cells, which then prevent development of metastases. In many ways, this study provides the missing piece of the jigsaw puzzle. There are several ongoing clinical trials of aspirin in certain cancers. The new insights from this study will now allow us to investigate data and materials from these trials to see if aspirin use can be personalised through use of biomarkers to achieve a more favourable benefit-harm balance. These insights will also allow us to develop new studies to investigate if aspirin and other immune-directed therapies can work in a synergistic manner to improve outcomes in advanced cancers.  

“It is important to acknowledge that since it aimed to elucidate a specific mechanism, the study looked at only a few cancer types and only at lung and liver as metastatic sites. Although different cancers share many common pathways, each cancer type (and subtype) is unique. This means that the magnitude of effect likely varies between different cancers. It is therefore quite possible that the beneficial effects of aspirin will be limited to certain cancer types as the epidemiological data suggest. We will need to wait for mature data from the current trials before aspirin’s use as a cancer treatment can be considered.

“If you are a cancer patient, don’t rush to your local pharmacy to buy aspirin just yet, but actively consider participation in ongoing or upcoming trials of aspirin.”

Professor Alan Melcher, Professor of Translation Immunotherapy at The Institute of Cancer Research, London, said:

“We have known for some time that aspirin can potentially boost the immune response to cancer. What this research tells us is a new mechanism of action that aspirin may be using to do this in mice.

“This is an interesting finding but will not directly change how people should be using aspirin. The side effects of the drug are not trivial – such as stomach bleeding. Currently, there are large trials underway to determine the risk versus benefit of using aspirin as part of the treatment of cancer. This new research may help to design better, more targeted drugs, that interfere with the mechanism discovered here to do the good things that aspirin does, without the harmful side effects.”

‘Aspirin prevents metastasis by limiting platelet TXA2 suppression of T cell immunity’ by Jie Yang et al. will be published in Nature at 16:00 UK time on Wednesday 5 March 2025.

DOI: 10.1038/s41586-025-08626-7

Declared interests

Prof Mangesh Thorat: No Financial interests to declare. Mangesh Thorat is a member of data monitoring committees of a few multi-national trials investigating aspirin, for example, ADD-Aspirin, CaPP3 and COLOPREVENT.

Professor Alan Melcher: no interests to declare.

Dr Harvey Roweth: Confirmed no COI’s.