Researchers at Weill Cornell Medicine, Memorial Sloan Kettering Cancer Center, and University of California San Diego Health have discovered that blood clots in cancer patients originate from the lungs, not other organ sites as previously believed.
Blood clots are the second-leading cause of death among patients with advanced or aggressive tumors.
Published in *Cell* on February 11, 2025, the study shows that tumors release chemokines, which circulate to the lungs and prompt immune cells called macrophages to emit small vesicles. These vesicles attach to platelets and form dangerous clots.
“This work redefines how thrombosis develops in cancer patients,” said Dr. David Lyden of Weill Cornell Medicine. “It’s a revolutionary concept that thrombosis is initiated in the lung.”
Co-senior authors Dr. Diane Simeone (UC San Diego Health) and Dr. Jacqueline Bromberg (Memorial Sloan Kettering) emphasized the importance of understanding clot risks in cancer. Many patients die from clots, not cancer, but predicting who is at high risk remains challenging.
The researchers found that tumors secrete varying levels of CXCL13. Breast cancers and melanomas release less, unless they spread to the lungs. Pancreatic tumors secrete high levels of CXCL13 into the bloodstream, activating lung macrophages remotely.
These macrophages then produce vesicles containing integrin β2, which can bind to platelets and cause clot formation. Blocking this process with an antibody prevented clots and reduced metastases in mice—without causing excessive bleeding.
Researchers suggest integrin β2 could also serve as a biomarker for clot risk. Analysis of blood samples from pancreatic cancer patients supported its predictive potential.
Dr. Lyden concluded, “Cancer is a systemic disease. We must address both metastasis and systemic complications like thrombosis.”
If you care about cancer, please read studies about A common blood thinner can help fight cancer and findings of Heavy alcohol drinking is common in cancer patients.
For more information about cancer, please read studies about Catching the silent killer: a new study on esophageal cancer and findings of New trick knocks out tough guy prostate cancer.
The study is published in Cell.
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