A new study from NYU Langone Health has found that cutting off blood flow in the body can make the immune system act older, which may allow cancer to grow faster.
This study, published in the journal JACC: CardioOncology, shows that limited blood flow—also known as ischemia—can make breast tumors grow twice as fast in mice.
Ischemia happens when arteries become blocked by fatty buildup like cholesterol. This reduces the flow of oxygen-rich blood, causing damage to tissues. When this occurs in the legs, it’s called peripheral artery disease. Millions of people in the U.S. have this condition, which also raises the risk of heart attacks and strokes.
In this new study, scientists found that ischemia in the legs can cause breast cancer to grow faster. This surprising result suggests that the harmful effects of poor blood flow aren’t limited to the heart or legs—they may impact the whole body, including how well the immune system can fight cancer.
The lead researcher, Dr. Kathryn J. Moore, explained that the immune system normally works to detect and destroy cancer cells. It uses special stem cells in the bone marrow to make white blood cells that defend the body. But when blood flow is blocked, this balance is disrupted.
The researchers used mice with breast tumors and created a condition of limited blood flow in one of their legs. They then compared these mice to others with normal blood flow. They found that the mice with ischemia had larger tumors and weaker immune responses.
The reason? Ischemia changed how stem cells in the bone marrow worked. Instead of producing helpful immune cells like T cells that attack cancer, the bone marrow made more of another kind of cell called myeloid cells. These cells, such as macrophages and neutrophils, can actually suppress the immune system and help cancer grow.
The tumors in the mice also showed more of these suppressive cells, making it harder for the immune system to fight back. In fact, the immune system looked similar to that of an older person—less active and more tolerant of disease.
Even more concerning, the effects of ischemia seemed to last. The researchers found that the genetic makeup of the immune cells had been altered. The proteins that help control DNA access (called chromatin) were changed, making it more difficult for the immune system to switch on cancer-fighting genes.
Dr. Alexandra Newman, the first author of the study, said that these findings could lead to better cancer treatment strategies.
For example, people with poor circulation or peripheral artery disease might benefit from earlier cancer screenings. New treatments could also focus on lowering inflammation to keep the immune system stronger after blood flow is reduced.
The team plans to explore whether existing drugs that reduce inflammation can help reverse these changes and slow down cancer growth in people with blocked arteries.
In short, this study shows that keeping blood flowing properly is not just good for the heart—it also helps the immune system stay young and strong enough to fight off cancer.
The study is published in JACC: CardioOncology.
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