Role of cytokines in breast cancer

OBJECTIVE: Fatigue is a common problem among cancer patients andsurvivors, yet the mechanisms underlying the occurrence and persistence of thissymptom are not known. Activation of the immune system may evoke feelingsof fatigue, which are mediated by proinflammatorycytokines.Itis examinedwhether fatigued breast cancer survivors would show elevations inproinflammatory cytokines and markers of cytokine activity compared withnonfatigued survivors. Differences in lymphocyte subsets, cortisol, andbehavioral symptoms associated with proinflammatory cytokines were alsoassessed.Metods:This is areview article.Results:Fatigued breast cancer survivors had significantly higher serum levelsof several markers associated with proinflammatory cytokine activity thannonfatigued survivors, including interleukin-1 receptor antagonist (IL-1ra),soluble tumor necrosis factor receptor type II (sTNF-RII), and neopterin. Theywere also more likely to report behavioral problems that co-occur with fatiguein the context of immune activation. Fatigued survivors had significantly lowerserum levels of cortisol than the nonfatigued group as well as differences in twolymphocyte populations.Conclusions: Fatigued breast cancer survivors showed elevations in serummarkers associated with proinflammatory cytokine activity an average of 5years after diagnosis. Results suggest mechanisms through which enduringimmune activation may occur, including alterations in cortisol and inlymphocyte subsetsethods.

Keywords:

breast cancer , cytokines , fatiuge