The stress hormone epinephrine causes changes in prostate and breast cancer cells that may make them resistant to cell death, according to new research.

Scientists from Wake Forest University School of Medicine in the US say that the findings suggest that emotional stress may contribute to the development of cancer and may also reduce the effectiveness of cancer treatments.

Although several researchers have investigated the link between cancer and stress, this is the first time that a study has shown that stress directly changes cancer cells, according to researcher Dr George Kulik.

Levels of epinephrine, which is produced by the adrenal glands, are sharply increased in response to stressful situations and can remain continuously elevated during persistent stress and depression, according to previous research. Now, the researchers have found a direct link between these stress hormones and changes in cancer cells: a protein called BAD – which causes cell death – becomes inactive when cancer cells are exposed to epinephrine.

Kulik said the findings have several implications for patients and for researchers.

"It may be important for patients who have increased responses to stress to learn to manage the effects," said Kulik. "And, the results point to the possibility of developing an intervention to block the effects of epinephrine."

Kulik is now studying blood samples of prostate cancer patients to determine if there is a link between levels of stress hormones and severity of disease.

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