Blood-thinning drugs such as aspirin may help fight cancer by denying shelter to wandering tumor cells, U.S. researchers reported.

Experiments in mice showed that combining aspirin with an experimental anti-clotting drug slowed the growth and spread of breast and melanoma tumors.

Blood cells called platelets shelter and feed tumor cells in the bloodstream, making it easier for cancer to spread, or metastasize, the team at Washington University in St. Louis said.

Writing in the Journal of Cellular Biochemistry, they said inactivating platelets may help slow or prevent this spread.

The study could help support other findings that show people who take aspirin or similar drugs that affect a gene and protein called COX-2, including aspirin, ibuprofen and the COX-2 inhibitor Celebrex, have a lower risk of some cancers.

There is also some suggestion that taking aspirin or ibuprofen along with chemotherapy may make the chemo more effective.