Serum interleukine-6 concentration, but not interleukine-18, is associated with head and neck squamous cell carcinoma progression.

Inflammation has been linked to various steps in tumorigenesis. Interleukin (IL)-6 and IL-18 are two inflammatory cytokines whose serum concentrations are elevated in several types of cancer, including head and neck squamous cell carcinoma (HNSCC) in some studies. This study was designed to analyze the serum concentrations of these cytokines in Iranian HNSCC patients. Serum IL-6 and IL-18 concentrations were assayed by ELISA commercial kits in 65 untreated patients and 20 healthy volunteers. Serum IL-6 concentration was significantly increased in patients compared to healthy individuals (p < 0.000). IL-6 concentration increased as the tumor stage progressed, and a significant difference appeared between stage IV vs. stage I/II/III (p = 0.03) disease. Although serum IL-18 concentration was higher in patients than in healthy individuals, the difference was not statistically significant (p = 0.06). Moreover, there was no association between serum IL-18 concentration and tumor stage (p = 0.47). A significant difference was observed in serum IL-18 concentration according to the gender with higher IL-18 concentration in male patients (p = 0.01). In conclusion, serum concentration of IL-6 might correlate with the stage of tumor progression in Iranian HNSCC patients. Further studies with larger numbers of patients are required to exclude the possible minor correlation of serum IL-18 concentration with tumor stage.