TEL AVIV — Researchers at Tel Aviv University's Gray Faculty of Medical and Health Sciences identified a mechanism by which cancerous tumors redirect a normal immune system process to support tumor growth. The study was published in the journal Science Immunology.

The research, led by Dr. Merav Cohen, doctoral student Roi Balaban, and doctoral student Ori Moskowitz, focused on macrophages. Macrophages are immune cells responsible for removing damaged and dead cells from the body. The researchers found that within cancerous tumors, macrophages change their behavior in ways that promote tumor development.

The team developed a technology called Effero-seq to track changes in immune cells after they engulf dead cells. The researchers found that macrophages that consumed dead cancer cells underwent reprogramming that activated genes associated with tumor growth. The team used a melanoma model to examine the effects of these altered immune cells.

Macrophages that had consumed dead cancer cells encouraged the formation of new blood vessels inside tumors. These additional blood vessels supplied tumors with oxygen and nutrients. The researchers also found that these macrophages became less responsive to signals that normally trigger anti-cancer immune activity.

To corroborate their findings, the researchers analyzed data from patients with uveal melanoma, a form of eye cancer. Patients whose tumors showed higher expression of immune cells carrying the genetic signature identified in the study generally had lower survival rates.

"The better we understand these mechanisms, the better equipped we will be to develop treatments that block them and restore the immune system’s ability to fight cancer," Cohen said. "This research points to a new and promising therapeutic target, one that focuses not only on the cancer cells themselves, but also on the processes that enable them to thrive."