Researchers at the Hadassah Medical Organization and Hebrew University have found that the most common form of white blood cells, called neutrophils, contain at least three distinct subtypes. Some fight the development of cancer, while others provide a hospitable environment for their growth.
The research findings could lead to new cancer-fighting therapies that seek to boost the anti-tumor neutrophils while limiting the proliferation of pro-tumor neutrophils.
In the last decade new approaches to cancer have involved activating the patient’s immune system against cancer cells, while not harming nearby healthy cells. Recently, however, researchers have discovered that there are healthy cells which surround the tumor that play an important role in enhancing cancer development. Thus, while neutrophils, which comprise between 50-70 percent of all white blood cells, are traditionally associated with fighting infections, accumulating data suggest they also play an important role in tumor biology. The Hadassah-Hebrew University scientists, working with mouse tumors and human blood samples, found that in early stages of the disease, tumor-limiting neutrophils prevail, but as cancer progresses, the tumor-promoting neutrophil subpopulation becomes dominant. As the authors explain:
“We identified a heterogeneous subset of low-density neutrophils (LDNs) that appear transiently in self-resolving inflammation, but accumulate continuously with cancer progression. LDNs display impaired neutrophil function and immunosuppressive properties, characteristics that are in stark contrast to those of mature, high-density neutrophils (HDNs). Proper understanding of the effect of tumors on neutrophils, as well as the way these cells support or fight cancer, could help us develop strategies to direct the immune system against the tumor, and potentially improve cancer treatment in general and immunotherapy in particular."
The research study, led by Dr. Zvi Fridlender, at the Hadassah-Hebrew University Medical Center’s Institute of Pulmonary Medicine, and Dr. Zvika Granot, at the Hebrew University’s Institute for Medical Research Israel-Canada (IMRIC) in the Faculty of Medicine, is highlighted in "Phenotypic Diversity and Plasticity in Circulating Neutrophil Subpopulations in Cancer" in the January 22, 2015 on-line issue of Cell Reports.