Accumulating evidence suggests a role for inflammation in the development and progression of cancer. Our group recently identified a cytokine gene signature in lung tissue associated with lung cancer prognosis. Therefore, we hypothesized that concentrations of circulating cytokines in serum may be associated with lung cancer survival. Ten serum cytokines, namely interleukin (IL)-1beta, IL-4, IL-5, IL-6, IL-8, IL-10, IL-12, granulocyte macrophage colony-stimulating factor, interferon (IFN)-gamma, and tumor necrosis factor-alpha, were assessed in 353 non-small cell lung cancer cases from a case-control study of lung cancer in the greater Baltimore, Maryland area. Cytokines were measured using an ultrasensitive electrochemiluminescence immunoassay. IL-6 serum concentrations (>or = 4.0 pg/mL) were associated with significantly poorer survival in both African Americans [hazard ratio (HR), 2.71;95% confidence interval (CI), 1.26 - 5.80] and Caucasians (HR, 1.71;95% CI, 1.22 - 2.40). IL-10 (HR, 2.62;95% CI, 1.33 -5.15) and IL-12 (HR, 1.98;95% CI, 1.14 - 3.44) were associated with lung cancer survival only in African Americans. Some evidence for an association of tumor necrosis factor-alpha leves with survival in Caucasians was observed, although these results were not significant. These hypothesis-generating findings indicate that selected serum cytokine concentrations are associated with lung cancer survival, and indicate that further research is warranted to better understand the mechanistic underpinnings of these associations.
