White Blood Cells Promote Tumor Growth

white blood cells promote tumor growth

White blood cells promote tumor growth: A human neutrophil (purple) eating a bacterium (yellow)

New research finds that white blood cells promote tumor growth. Neutrophils, a common white blood cell, aren’t simply one type of cell, it actually are made up of different subtypes that can either accelerate growth of tumors or fight them!

Neutrophils are the most common white blood cell. The cells account for between 50 to 70% of circulating white blood cells. As you might already know, the role of these white blood cells is to fight invading pathogens protecting the body from harm. Neutrophils react to a hostile invader by both releasing immune system signal molecules called cytokines to stimulate an immune response and to act as soldiers outright killing the invaders. Neutrophils role in fighting cancer is somewhat dual since researchers have observed both positive and negative effects of the immune cells. Certain studies show that the white blood cell actually promotes growth and spread of cancer by stimulating blood vessel formation. Other studies have seen anti-tumor actions of the same cells. What is the true role of neutrophils in cancer? This is explored in new research from The Hebrew university of Jerusalem.

White Blood Cells Promote Tumor Growth and Prevents It!

The findings are published in Cell Reports.

In this study researchers investigated both mice with tumors and human blood samples to figure out the nature of neutrophils in cancer. They uncovered that these white blood cells aren’t all the same, sharing the same characteristics. Neutrophils are actually made up of different subtypes that are either “good” or “bad” for the growth of tumors. Some of these white blood cells promote tumor growth, others prevent it.

The difference lay in how long the tumor had been around. Researchers found that in the early phase of tumors neutrophils are made up of “normal” high density neutrophils (HDNs). These white blood cells have anti-tumor properties, working to stop tumor progression. Later on when tumors have progressed further researchers found a greater number of of LDNs, low density neutrophils. These white blood cells demonstrated a pro-tumor effect. Promoting tumor growth and stopping the immune system from attacking.

So why do these white blood cells change as tumors progress? It appears neutrophils can change from one type to another. The kicker is that this only occur one way, the bad one! As tumors progress they release a growth factor (TGF-beta) that changes “good” neutrophils into “bad” ones, LDNs. Further accelerating tumor growth.

“The novel distinction between harmful and beneficial neutrophils opens up new diagnostic and therapeutic opportunities. We are currently evaluating the effects of boosting the helpful anti-tumor neutrophil population, while limiting the tumor-promoting neutrophil population, on progression of the disease. If successful, this therapeutic strategy may take us closer to developing effective new therapies for cancer.” – Dr. Granot research leader.

As Dr. Granot mentions above this discovery opens up some new ways to treat cancer. Developing a treatment that can change “bad” white blood cells into “good” ones’ could help slow cancer growth resulting in better outcomes.

Image credit: NIAID via flickr.com, CC BY-2.0