Stress we encounter in our daily life triggers responses in our body that can make us more alert and increase our ability to react to threats. However, the signals the body sends to cells, such as the stress hormone adrenaline, can also be harmful.
Chronic periods of stress have been shown to affect our health, including that they promote the progression of cancer, and lead to increased mortality rates in cancer patients.
Cancer cells can spread around the body forming metastases. However, it was unclear how cancer cells escape from the site they have formed, and how this is promoted by the affects of stress.
Monash researcher Dr Erica Sloan and colleagues now have shown that in mice chronic stress restructures the architecture of the lymphatic system - a network of vessels which transports fluid around the body. In mice, chronic stress causes lymphatic vessels to increase in number and diametre.
Thus, rather than the lymphatic system just passively providing a route of transport, chronic stress leads to the formation of new lymphatic pathways that help cancers cells to escape.
In addition, the lymphatic system is rich with components of the immune system, some of which promote the invasiveness of tumour cells
Importantly, the study reveals potential targets for intervention: proteins through which cells are alerted by stress hormones.
Thus the authors show in both clinical and preclinical studies that blocking the activity of a receptor protein of adrenaline - the beta-adrenoreceptor - can prevent the spread of cancer cells.