In a new study published Wednesday in Science Translational Medicine, one group of researchers describes how a cascade of events set off by high levels of a stress hormone could cause dormant tumor cells to reawaken to once again cause cancer.

The hormone, norepinephrine, is naturally found in the body, but more of this chemical is released into the bloodstream when the body detects higher levels of stress. In some cancer models, scientists found that an elevated level of norepinephrine led to the activation of cells known as neutrophils, which help shield tumor cells from the body’s immune system. Activating neutrophils in turn led to these cells releasing a special type of lipid — which then awakened sleeping cancer cells.

Read more about the study here.