When working correctly, your immune system detects and responds to pathogens ranging from viruses to parasitic worms, as well as cancer cells and foreign objects such as wood splinters.

Researchers at Tel Aviv University recently discovered that the cells in certain cancer patients can act as “double agents,” helping cancerous tumors grow rather than eradicate them.

The study, published in the Cell Reports, found that immune cells called neutrophils play a critical role in interacting with cancerous growth. Neutrophils are continuously recruited from the bone marrow to do their job.

“Neutrophils are the front-line soldiers of the immune system,” said lead researcher Dinorah Friedmann-Morvinski. “When a tumor begins to develop, the neutrophils are among the first to mobilize and attack it in order to eliminate it.”

However, the researchers were surprised to find that neutrophils can “change sides.” Over time, they can be recruited to the cancerous area to support its development and speed the growth of tumors.

“As a result, they aggravate the damage that the tumor itself creates,” said Friedmann-Morvinski.

“The study showed that the change in the properties of neutrophils takes place in the bone marrow itself – where there is no tumor at all: the cancerous tumor is located only in the brain, and from there it succeeds in changing the properties of the cells it recruits,” adds Friedmann-Morvinski.

The new findings may shed light on a type of immunotherapy treatment where T-cells are removed from the patient, processed, and returned to the body with increased healing abilities.

“One of the major problems today is that even these cells that have been sent to heal are suppressed and their actions stifled. If we know how to change the interaction between neutrophils and T-cells so that they are not suppressed, this will have implications for the effectiveness of immunotherapy,” she said.

This study was led by Friedmann-Morvinski and her PhD student Prerna Magod. Also participating were Liat Rousso-Noori and Ignacio Mastandrea, also from the TAU Faculty of Life Sciences, as well as other researchers from the university’s Sackler Faculty of Medicine and from the Weizmann Institute of Science.