It is already known that aspirin helps prevent not only cardiovascular disease, but also cancers such as colorectal cancer and increase the survival rate of cancer patients. However, mechanisms have remained unclear. Recent study has identified previous unknown mechanism that aspirin could prevent incidence of cancer by effecting blood cells called platelets rather than inhibiting cancer cell directly.

Owen McCarty, a professor in the department of biomedical engineering at Oregon health and science university, has identified the mechanism by which aspirin inhibits the formation of cancer cells and published the findings in the American Journal of Physiology (AJP-Cell Physiology).

“Aspirin does not directly affect cancer cells, but it indirectly affects the growth and metabolism of cancer cells by affecting platelet activity, one of the blood components,” McCarty said. Platelets are involved in blood coagulation, but they also promote activation of c-MYC tumor protein. The c-MYC protein regulates gene expression in about 15% of the various genes in the human body and is involved in cell biology, protein synthesis, and cellular metabolism regulation. It also supports cancer cells and helps spread them. Many of the patients with some cancers, such as about 30% of colon cancer patients and 42% of pancreatic cancer patients, have over-expressed oncogenes and increased c-MYC tumor protein. However, studies have shown that aspirin reduces platelet activity and inhibits this protein production. According to McCarty’s explanation, cancer cells initially live in very hostile environments in the body. Because the human immune system continually attacks and attempts to eliminate it.

Platelets interact with cancer cells and protect cancer cells from immune system. The researchers concluded that aspirin could inhibit the activity of platelets and c-MYC proteins to prevent cancer.

McCarty said that the new findings aren’t sufficient to justify taking aspirin solely to help prevent cancer. However, the researchers pointed out that the findings might have implications for aspirin therapy in conditions in which platelet activation is important, such as beginning of intravasation which is early stage of invasion through basal membrane into blood or lymphatic vessel. Because the interaction between platelets and cancer cells can begin early following the invasion of cancer cells into the blood stream, low doses of aspirin might eventually prove safe and effective as a way to prevent cancer in patients at risk.