Aspirin combined with immunotherapies could help the body fight cancer, new research suggests.
The study found that aspirin suppresses a molecule that allows tumors to evade the body's immune defenses. Researchers said that the findings could make a huge difference in the fight against cancer.
Tests showed that skin, breast and bowel cancer cells generate large amounts of the molecule, prostaglandin E2 (PGE2).
Aspirin and other members of the 'Cox inhibitor' drug family block production of the molecule so that tumors have nowhere to hide.
Researchers tested in mice, combing immunotherapy - which equips the immune system to attack cancerous cells - with aspirin or other Cox inhibitors was found to substantially slow the growth of bowel and malignant skin cancer.
Professor Caetano Reis e Sousa, who led the team from the Francis Crick Institute in London, said, "We have added to the growing evidence that some cancers produce PGE2 as a way of escaping the immune system. If you can take away cancer cells' ability to make PGE2, you effectively lift this protective barrier and unleash the full power of the immune system."
"Giving patients Cox inhibitors like aspirin at the same time as immunotherapy could potentially make a huge difference to the benefit they get from treatment. It's still early work but this could help make cancer immunotherapy even more effective, delivering life-changing results for patients," said Reis e Sousa.
Professor Peter Johnson, chief clinician at Cancer Research UK, which funded the study, said, "PGE2 acts on many different cells in our body, and this study suggests that one of these actions is to tell our immune system to ignore cancer cells. Once you stop the cancer cells from producing it, the immune system switches back to "kill mode" and attacks the tumor."
"This research was carried out in mice so there is still some way to go before we will see patients being given Cox inhibitors as part of their treatment. But it's an exciting finding that could offer a simple way to dramatically improve the response to treatment in a range of cancers," he added.