Metastasis, the spread of cancer from the primary tumor to other parts of the body, is the main cause of death from breast cancer. The body’s macrophages are known to facilitate the growth of metastatic lesions in other parts of the body.

In a study published online on September 5 in Cancers involving a mouse model of breast-cancer metastasis, David Entenberg, Ph.D., John Condeelis, Ph.D., Jeffrey Pollard, Ph.D., and colleagues used advanced imaging techniques to directly visualize breast-cancer cells as they interact with macrophages within the first few hours after arriving in the lungs. The researchers found that macrophages rely on a signaling pathway involving the cytokine interleukin-4 (IL-4) to communicate with tumor cells and help them to seed and grow in the lung. They also showed that inhibiting the IL-4 signaling pathway leads to fewer and smaller lung metastases. The discoveries reveal a new strategy—inhibition of IL-4—for treating and possibly preventing lung metastases.

Dr. Entenberg is an associate professor of pathology and co-director of the Gruss Lipper Biophotonics Center at Einstein. Dr. Condeelis is the Judith & Burton P. Resnick Chair in Translational Research, and director of the Integrated Imaging Program for Cancer Research at Einstein. Dr. Pollard is professor emeritus of developmental and molecular biology, and of obstetrics & gynecology and women’s health, and is the Louis Goldstein Swan Chair in Women's Cancer Research Emeritus at Einstein and is currently at the University of Edinburgh.