Prognostic value of circulating cytokines on overall survival and disease-free survival in cancer patients.

Through their tumor-promoting and/or tumor-suppressive properties, cytokines can influence progression of cancer. We systematically reviewed the current literature on the prognostic value of the circulating cytokines IL-1α/β, IL-6, IL-8, IL-10, IL-12, TNF-α, TGF-β and IFN-γ to predict overall and disease-free survival in any type of cancer patients. PubMed was systematically searched and based on eligibility assessment using our five criteria of the Reporting Recommendations for Tumor Marker Prognostic Studies (REMARK) checklist, six unique studies were reviewed. Elevated IL-6 and IL-10 levels seem independently associated with worse prognosis in terms of overall and disease-free survival. The prognostic value of IL-1α/β, IL-8, IL-12, TNF-α, TGF-β and IFN-γ could not be demonstrated. The small number of selected studies underlines the need for large well-designed prospective studies, using the REMARK checklist as a guideline, to determine which cytokines have prognostic value on survival in cancer patients.