An inflammatory process begins when damaged tissues release certain chemicals, including histamines and prostaglandins. In response, white blood cells travel to the damaged tissues and produce substances that cause cells to divide and grow to rebuild tissue. The inflammatory process ends when the injury has been healed.

When inflammation occurs at the wrong times or becomes chronic, however, problems can arise. Many researchers describe inflammation as a double-edged sword.

On the one hand, the immune system is constantly vigilant, monitoring the body for foreign invaders, such as pathogens.

In some cases, tumor cells may take advantage of the inflammatory environment to actually exclude tumor-fighting immune cells.

The immune system is also on alert for threats from inside the body—that is, tumors. “Scientists have observed that there may be tumor cells in our bodies that we never know about, because the immune system is going out and killing those tumor cells."

What’s more, cancer treatments such as immunotherapy may kill cancer cells by activating some of the inflammatory processes used to fight pathogens. So, researchers have been studying the interplay between inflammation and immunotherapy.

In short, there is evidence that inflammation may both promote and constrain tumors. Over the past decade, researchers have used this knowledge to explore new treatments for cancer, including anti-inflammatory drugs.