Aim:
Background: Oral squamous cell carcinoma is one of the frequent form of malignancy, which has different molecular subtypes. Interleukin-17 (IL-17), a pro-inflammatory cytokine, might be one of the factors associated with tumor biology as well as oral findings. Objectives: To assess the level of salivary IL-17 in Oral Squamous Cell Carcinoma patients compared to healthy individuals and their association with molecular etiology and oral manifestations.

Material and methods:
Materials and methods: A case-control study was carried out in 56 patients with OSCC and 46 healthy matched subjects. The demographics, tumor molecular profiles (TP53 mutations and EGFR overexpression), and oral examination findings were systematically recorded. ELISA was used to detect the concentration of IL-17 in saliva.

Results:
Salivary IL-17 levels were significantly elevated in patients with Oral Squamous Cell Carcinoma (21.34 ± 4.6 pg/mL) compared to the control group (19.72 ± 4.2 pg/mL, p = 0.040). IL-17 was higher in TILs of those patients; tumors with overexpression of EGFR exhibited higher levels than those with TP53 mutations. The most common oral manifestations observed in this study included mucositis and xerostomia. The increase in salivary IL-17 was also found to be independently associated with mucosal alterations and changes in pigmentation.

Conclusions:
Conclusion: salivary IL-17 levels were elevated in patients with Oral Squamous Cell Carcinoma, with this biomarker being correlated in such cases with tumors driven by EGFR and with specific oral manifestations. Thus, this biomarker has the potential to be a non-invasive tool for disease detection and follow-up.