‘Stress Causes Cancer To Spread By Supercharging Blood Vessels That Move Fluid Around Body’
Stress causes cancer to spread by supercharging a network of blood vessels which move fluid around the body, new research has found.
Scientists discovered cancerous cells increased when the ‘lymphatic system’, which carries infection fighting cells but also moves diseased ones to new sites, is affected by stress hormones.
The study was carried out on mice but the breakthrough offers hope of new treatments for humans.
Stress has long been linked to many forms of the disease including breast and prostate tumours but the reason has remained a mystery.
There is evidence it’s associated with increased mortality in cancer patients and with more advanced tumours in animals.
Previous work has described how 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 until now.
Research by Dr Erica Sloan, of Monash University in Victoria, Australia, has shown the lymphatic system is affected by stress hormones, and this can result in the spread of cancer cells in mice.
Cancer beating treatment to be trialled in UK after successful tests in America In a series of experiments they found lab rodents genetically engineered to develop cancer had more and lymphatic vessels coming from their tumours when exposed to stress.
They were also wider in diameter.
Under powerful microscopes they were also able to see stress hormones boosted the flow of fluorescently labelled cancer cells through the lymphatic system.
And by blocking their activity – or proteins that enhance formation of the vessels – they reduced the spread in the mice – offering hope of new treatments for humans.
Dr Sloan said: “Chronic stress induces signalling from the sympathetic nervous system (SNS) and drives cancer progression, although the pathways of tumour cell dissemination are unclear.
“Here we show chronic stress restructures lymphatic networks within and around tumours to provide pathways for tumour cell escape.
“These findings suggest limiting the effects of SNS signalling to prevent tumour cell dissemination through lymphatic routes may provide a strategy to improve cancer outcomes.”
She added it may be important to identify stressed individuals who may be particularly susceptible to spreading lymph vessels.
One approach may be through blood tests using a stress chemical signature.
Alternatively, as cancer is often a highly stressful experience, targeting the SNS with drugs may be generally useful to improve cancer outcome.
It is known stressful events can alter the levels of hormones in the body and affect the immune system.
But there was no evidence that these changes could lead to cancer.
Emma Smith, senior science communication officer at Cancer Research UK, said: “Most cancer patients will naturally feel stressed and upset at points during their illness and treatment but there’s currently no strong evidence stress levels affect the chances of surviving cancer.
“Stress is a highly complex emotion in humans that’s very difficult to replicate in mice.
“What is interesting about this study is it adds to our understanding of the role particular hormones and inflammation play in cancer spread, and is another step towards understanding how anti-inflammatory drugs could play a part in effective cancer therapy.”
The findings are published in Nature Communications.