The isolated mice also had a higher corticosterone stress hormone response than did the group-housed mice.
The changes in the expression levels of metabolic pathway genes occurred in the isolated mice even before the tumor size differences were able to be measured, Conzen said.
So what are the practical applications of the research?
The findings may suggest molecular biomarkers, or targets, for preventive intervention in breast cancer, she said.
"Many questions remain," Conzen added. "One of the things we did note is that the isolated animals were much more vigilant, less exploratory. They released more of a stress hormone when we added another stressor to the situation [besides the isolation]."
Thea Tisty, a pathology professor at the University of California, San Francisco, who is familiar with the findings, called the research "a very exciting beginning."
The implication is that perceived or actual stress from outside can affect which genes get turned on or off. If the research findings bear out, it could lead to a way to catch tumors in their formation before they become tumors and suppress them, she said.
Another expert speaking at the briefing cautioned that the findings, while exciting, are only preliminary and based only on animal studies.
"This is an area that has a long way to go in terms of understanding how these factors play out in humans," said Caryn Lerman, the Mary W. Calkins Professor of Psychiatry at the Abramson Cancer Center at the University of Pennsylvania in Philadelphia.
To learn more about stress and cancer, visit the National Cancer Institute.
SOURCES: Suzanne D. Conzen, M.D., associate professor of medicine, Ben May Department for Cancer Research, Univ
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