Using tissue samples from 15 of the patients with the most significant symptoms of depression and 15 samples from the patients with the mildest forms of depression, the researchers then conducted whole-genome profiling to determine if the depression is linked to increased risk of death for cancer patients.
They found specific signaling pathways, which play a key role in regulating cell inflammation, were expressed at increased levels in patients with depression. The study authors concluded the link between patients' mental health and survival time is associated with inflammatory gene regulation.
"Our findings indicate that we're now able to understand some of the possible biological pathways that explain the association between depression and survival," Cohen noted.
The researchers noted that the study was limited by the fact that it's difficult to determine if patients' stress or symptoms of depression are influenced by other factors or were present before their cancer diagnosis. While the study uncovered an association between depression and cancer survival, it did not prove a cause-and-effect relationship.
More research is needed to investigate if the treatment of depression can improve survival time among cancer patients with mild, moderate or severe mood disorders, the authors added.
The U.S. National Cancer Institute has more about cancer and depression.
-- Mary Elizabeth Dallas
SOURCE: University of Texas M.D. Anderson Cancer Center, news release, Aug. 1, 2012
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