Fatigue is highly prevalent in the general population and is one of the most common side effects of cancer treatment. There is growing evidence that pro-inflammatory cytokines play a role in cancer-related fatigue, although the molecular mechanisms for chronic inflammation and fatigue have not been determined. The current study utilized genome-wide expression microarrays to identify differences in gene expression and associated alterations in transcriptional activity in leukocytes from breast cancer survivors with persistent fatigue (n=11) and non-fatigued controls (n=10). We focused on transcription of inflammation-related genes, particularly those responsive to the pro-inflammatory NF-κB transcription control pathway. Further, given the role of glucocorticoids as key regulators of inflammatory processes, we examined transcription of glucocorticoid-responsive genes indicative of potential glucocorticoid receptor (GR) desensitization. Plasma levels of cortisol were also assessed. Consistent with hypotheses, results showed increased expression of transcripts with response elements for NF-κB, and reduced expression of transcripts with response elements for glucocorticoids (p<.05) in fatigued breast cancer survivors. No differences in plasma levels of cortisol were observed. These data indicate that increased activity of pro-inflammatory transcription factors may contribute to persistent cancer-related fatigue and provide insight into potential mechanisms for tonic increases in NF-κB activity, specifically decreased expression of GR anti-inflammatory transcription factors.
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