Stress hormones enhance the spread of cancer by affecting the lymphatic system - a network of vessels which transports fluid around the body - reports a study in mice published in Nature Communications this week.
There is evidence that stress is associated with increased mortality in cancer patients and with advanced stages of cancer progression in animals. Previous work has described that stress hormones can influence blood vessel formation, which is important in the spread of disease. The lymphatic system can also promote the spread of cancer, but whether this can be influenced by stress has been unclear up to now.
Erica Sloan and colleagues show that the lymphatic system is affected by stress hormones, and that this can result in the spread of cancer cells in mice. They study five or more mice across a number of experiments and show that stress increases the number and diameter of lymphatic vessels associated with tumours. Using special microscopy, the authors demonstrate that stress hormones can increase the flow of fluorescently labelled nanoparticles through the lymphatic system. By blocking the activity of proteins that detect stress or those that enhance formation of the lymphatic vessels, they could reduce the spread of cancer cells in the mice.
These findings in mice suggest that targeting this stress pathway may be useful in blocking the spread of cancer cells.