"These data imply that emotional stress may contribute to the development of cancer and may also reduce the effectiveness of cancer treatments," said George Kulik, D.V.M., Ph.D., an assistant professor of cancer biology and senior researcher on the project.
The study results are reported on-line in the Journal of Biological Chemistry and will appear in a future print issue.
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. The goal of the current study was to determine whether there is a direct link between stress hormones and changes in cancer cells.
While a link between stress and cancer has been suggested, studies in large groups of people have been mixed.
"Population studies have had contradictory results," said Kulik. "We asked the question, ‘If stress is linked to cancer, what is the cellular mechanism??There had been no evidence that stress directly changes cancer cells."
Studying prostate and breast cancer cells in the laboratory, Kulik and colleagues found that a protein called BAD ?which causes cell death ?becomes inactive when cancer cells are exposed to epinephrine.
Kulik said that connection between stress and prostate cancer has been largely unexplored. However, recent studies suggest that these laboratory findings may apply to cancer patients.
"A study from Canada showed that men who took beta blockers for hypertension for at least four years had an 18 percent lower risk of prostate cancer," said Kulik. "These drugs block the effects of epinephrine, which could explain the finding.
Source:Wake Forest University Baptist Medical Center