Cytokine expression profiles in the sera of cutaneous squamous cell carcinoma patients

We focused on the interaction of cytokines in squamous cell carcinoma (SCC), and determined the expression profile of multiple cytokines in the serum of each patient with SCC in the present study. Serum samples were obtained from 12 SCC patients and 7 normal subjects. Four cytokines (IFN-γ, IL-6, GM-CSF, and TGF-β) were selected because they are reported to be involved in keratinocyte proliferation and SCC progression. Serum levels were measured using ELISA. We found a statistically significant increase of serum IFN-γ levels in SCC patients compared to those in normal subjects, and areas under the curve (AUC) of 0.82 for the serum levels of IFN-γ were higher than those for other cytokine levels according to ROC curve analysis. Patients with increased IFN-γ levels had a significantly more severe cancer stage. Furthermore, the combination of IFN-γ levels and TGF-β levels could improve the AUC to 0.84. We also found there was a significant correlation between IFN-γ levels and GM-CSF levels or between GM-CSF levels and TGF-β levels only in SCC patients. Our results suggest that the combination of IFN-γ levels and TGF-β levels is more effective to diagnose SCC, while serum levels of IFN-γ alone are useful to evaluate tumor progression. Furthermore, expression of these cytokines was not independent, but may be regulated by common upstream factors (e.g. cytokines or methylation) in SCC patients, and such factors may play some roles in the pathogenesis of SCC.