Stress is implicated in increased tumor progression risk and poor survival in cancer patients. A number of recent studies have linked these effects to the promotion of tumor cell dissemination through the bloodstream via stress-induced pathways. Now, a mouse study led by researchers in Australia has revealed the mechanisms by which stress modulates cancer’s spread through another transport network open to tumor cells—the lymphatic system. The findings were published today (March 1) in Nature Communications.
“Stress not only affects your well-being, but it also affects your biology,” said study coauthor Erica Sloan, a cancer researcher at Monash University in Melbourne. “Our study particularly highlights the early steps of tumor cell dissemination into the lymphatic system.”
“This is an excellent contribution,” said Kari Alitalo, a professor of translational cancer biology at the University of Helsinki, Finland, who was not involved in the study. “It’s certainly a very refreshing, novel aspect of biology that they explore in this paper.”
Chronic stress, mediated partly through the sympathetic nervous system, has been associated in cancer patients with a number of physiological changes that promote metastasis (the spread of cancer), including the promotion of blood vessel formation and the recruitment of inflammatory cells like macrophages.
To investigate whether stress could also induce changes in lymph vasculature, the researchers subjected various types of mammary tumor–bearing mice—including strains genetically engineered to develop tumors spontaneously, as well as animals given tumor transplants—to a paradigm designed to induce chronic stress: confinement in a tight space. Comparing stressed mice to controls that bore the same cancerous tumors but had been kept in normal cage conditions, the researchers found no difference in primary tumor growth, but significant differences in lymph vasculature architecture and the frequency of metastases.
