Evaluation of Serum and Salivary Interleukin-6 and Interleukin-8 Levels in Oral Squamous Cell Carcinoma Patients: Systematic Review and Meta-Analysis

This meta-analysis aimed to assess the salivary and serum concentrations of IL-6 and IL-8 in oral squamous cell carcinoma (OSCC) patients compared to the controls. Four electronic databases (Scopus, PubMed, Cochrane Library, and Web of Science) were searched up to January 2019. The study quality was checked according to the Newcastle-Ottawa Scale. The mean difference (MD) plus 95% confidence interval (95%CI) were calculated using RevMan 5.3 software. The publication bias and sensitivity analysis were done using CMA 2.0 software. Out of 309 studies retrieved from the 4 databases, 26 studies were analyzed in the present meta-analysis. In this meta-analysis, the pooled MD in the OSCC patients compared to the controls was 19.06 pg/mL (95%CI: 14.78-23.33) for the serum IL-6 level, 199.14 pg/mL (95%CI: 47.39-350.89) for the serum IL-8 level, 122 pg/mL (95%CI: 64-179) for the salivary IL-6 level, and 958 pg/dL (95%CI: 718-1197) for the salivary IL-8 level. All values in this meta-analysis were statistically significant. In conclusion, according to the meta-analysis results, the serum and salivary IL-6 and IL-8 levels in OSCC patients were significantly elevated compared to the controls, and both cytokines can be useful as potential biomarkers in early OSCC diagnosis.