It’s normal and inevitable to have bouts of stress—if you’re running late for a meeting, interviewing for a new job, or worrying about a friend.
But long-term stress that seems to be a lingering undercurrent of your life can really take a toll on your health.
Research has linked chronic stress to an increased risk of heart disease and stroke.
A 2017 study published in The Lancet found links between stress and episodes of cardiovascular disease.
Another published in 2022 found that a major stressful life event can increase the risk of a first stroke by 17 percent.
According to Cancer Research UK, there is no evidence that stress can directly increase your risk of cancer.
“However, some people may find it harder to maintain their health during periods of stress, which can lead to an increased risk of cancer,” the charity explained.
Now, new research has shown that stress can make cancer more likely to spread if you already have the disease – and revealed the mechanisms behind it.
Xue-Yan He, a former postdoctoral fellow at Cold Spring Harbor Laboratory (CSHL), said: “Stress is something that we really cannot avoid in cancer patients.
“You can imagine when you’re diagnosed, you can’t stop thinking about the disease, insurance, or family.
“So it’s very important to understand how stress affects us.”
CSHL researchers found that stress causes certain white blood cells called neutrophils to form sticky web-like structures.
They make the body’s tissues more prone to metastasis – the spread of cancer cells from where they first formed to another part of the body – they said.
This new finding could help find new treatment strategies to stop the spread of cancer, the researchers added.
For their study, the CSHL team used mice that mimicked the effects of chronic stress to see how it would affect cancer in rodents.
First, they removed tumors that were growing in the mice’s breasts and spreading cancer cells to their lungs.
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Next, they exposed the mice to stress.
The researchers observed “an alarming increase in metastatic lesions in these animals.”
Associate Professor Mikala Egeblad said: “It was up to a fourfold increase in metastases.”
The team discovered that stress hormones called glucocorticoids act on neutrophils.
These “stressed” neutrophils have formed web-like structures called NETs (neutrophil extracellular traps), which form when white blood cells expel DNA.
Normally, neutrophils can defend the body against invading microorganisms.
But in mice with cancer, NETs created an environment favorable for metastasis.
Dr. He performed three tests to confirm that stress triggers the formation of NETs, which can lead to increased metastasis.
First, she used antibodies to remove neutrophils from mice.
She then injected the animals with a NET-destroying drug.
Finally, she used mice whose neutrophils could not respond to glucocorticoids.
Similar results were observed in all three tests.
“The stressed mice no longer developed additional metastases,” said Dr.
The team also found that chronic stress caused NET formation to modify lung tissue even in cancer-free mice.
Dr. Egebald explained, “Your tissue is almost ready for cancer.”
