Study Finds Tumors Can Turn Immune Cells Into Cancer Supporters - Video

New research has revealed how tumors can manipulate the body’s immune system to support their own growth. Scientists at the University of Geneva (UNIGE), working with the Ludwig Institute for Cancer Research, have discovered that neutrophils — a common type of immune cell — can be reprogrammed by tumors to help cancer grow instead of fighting it. The findings were published in the journal Cancer Cell.

Neutrophils normally act as the body’s first line of defense against infections and injuries. However, the study found that once these cells enter the tumor environment, they change their behavior. Tumors attract neutrophils and alter their activity, causing them to produce a molecule called CCL3. Instead of protecting the body, CCL3 promotes tumor growth.

When researchers removed the CCL3 gene specifically from neutrophils, the cells no longer supported tumor development. Importantly, the neutrophils still functioned normally in the bloodstream and were able to enter tumors, but they did not assist cancer growth. This shows that CCL3 plays a key role in turning neutrophils into tumor promoters.

Studying neutrophils is technically challenging because they are difficult to manipulate genetically. To overcome this, the research team used several advanced experimental approaches to control CCL3 production only in neutrophils without affecting other cells.

The team also analyzed data from multiple cancer studies. Using new bioinformatics tools, they confirmed that high CCL3 production by neutrophils is seen across many cancer types and is linked to more aggressive disease.

Researchers believe CCL3 could serve as a useful marker to track tumor progression. Identifying such key factors may help doctors better predict how cancer will evolve and develop more personalized treatment strategies in the future.

REFERENCE: Evangelia Bolli, Pratyaksha Wirapati, Mehdi Hicham, Yuxuan Xie, Marie Siwicki, Florent Duval, Anne-Gaëlle Goubet, Máté Kiss, Béatrice Zitti, Thomas Zwahlen, Sheri Mcdowell, Ruben Bill, Simona Angerani, Camilla Engblom, Seth Anderson, Aiping Jiang, Oliver Hartley, David B. Sykes, Maja Jankovic, Nadine Fournier, Matthias Gunzer, David Tarussio, Stéphanie Tissot, Peter M. Sadow, William C. Faquin, Moshe Sade-Feldman, Ralph Weissleder, Sara Pai, François Mercier, Robert Manguso, Mikaël J. Pittet. CCL3 is produced by aged neutrophils across cancers and promotes tumor growth. Cancer Cell, 2026; DOI: 10.1016/j.ccell.2026.01.006