Salivary interleukin-10 and interleukin-17 - Potential biomarkers for assessing oral cancer and oral potentially malignant disorders - A comparative study.

Background: Staging of oral squamous cell carcinoma (OSCC) and oral potentially malignant disorders (OPMDs) is considered as the most important prognostic indicator, but salivary proteins such as interleukins (ILs) can serve as potential biomarkers. The aim of this study was to assess the presence of salivary IL-10 and IL-17 in OSCC and OPMD (oral submucous fibrosis and oral leukoplakia).

Materials and methods: This was a hospital-based, in vivo, cross-sectional, comparative study. A total of 90 patients (N = 90) were included in the study. Whole unstimulated saliva was collected and subjected to enzyme-linked immunosorbent assay (ELISA): 30 from histopathologically confirmed OSCC (Group 1, n = 30), 15 from clinically diagnosed OSMF (Group 2, n = 15), 15 from clinically diagnosed OL (Group 3, n = 15), 15 from patients who had tobacco habits but no clinical lesions of OSCC/OL/OSMF (Group 4, n = 15), and 15 from healthy controls (Group 5, n = 15).

Results: Statistical analysis was performed by SPSS®25.0 (analysis of variance [ANOVA], Tukey's post hoc test, and Mann-Whitney U test). Both IL-10 and IL-17 were found in saliva. One-way ANOVA between groups showed IL-10 did not vary significantly within groups (P = 0.853), but IL-17 varied significantly between groups (P = 0.000). Mann-Whitney U test used to compare IL-10 and IL-17 between stage III and IV of OSCC showed that they did not vary significantly.

Conclusion: IL-17 can indicate the presence of ongoing inflammation toward developing OPMD/OSCC, proving it as a potent diagnostic biomarker. An increase in IL-17 with successive stages of OSCC proves it as a prognostic biomarker for OSCC.