# Serum Interleukin‐35 Levels in Oral Squamous Cell Carcinoma and Salivary Gland Tumors: Implications for Early Detection and Prognosis

## TL;DR

This study explores serum interleukin-35 (IL-35) levels in oral cancer and salivary gland tumors, finding reduced levels in salivary gland tumors but not in oral squamous cell carcinoma.

## Contribution

The study identifies IL-35 as a potential biomarker for salivary gland tumors but not for oral squamous cell carcinoma.

## Key findings

- IL-35 levels were significantly lower in salivary gland tumor patients compared to controls.
- No significant difference in IL-35 levels was found between benign and malignant salivary gland tumors.
- IL-35 levels in oral squamous cell carcinoma patients did not differ significantly from controls.

## Abstract

Oral cancer, particularly oral squamous cell carcinoma (OSCC), is a major global health concern, with late‐stage diagnoses significantly lowering survival rates. Salivary gland tumors (SGTs), though less common, pose diagnostic challenges due to their varied presentation. This study investigates the role of interleukin‐35 (IL‐35) in OSCC and SGTs, aimed at assessing its potential as a biomarker for early detection and prognosis.

A cross‐sectional study was conducted, including 65 OSCC patients, 65 SGTs patients, and 50 healthy individuals as a control group. Inclusion criteria included age over 18 years, negative HPV confirmation, and histopathologically confirmed cancer diagnosis (SGT or OSCC). Blood samples were collected from all participants. Serum IL‐35 levels were measured using the ELISA kit.

IL‐35 levels varied significantly between the groups (p = 0.002), with the lowest levels detected in the SGT group. Pairwise comparisons revealed that IL‐35 levels were significantly lower in the SGTs patients (5.45 ± 6.03 pg/mL) compared to both the OSCC group (9.21 ± 10.81 pg/mL, p = 0.002) and the control group (10.50 ± 11.77 pg/mL, p = 0.004). IL‐35 levels were significantly lower in patients with malignant SGTs (5.45 ± 6.03 pg/mL) compared to healthy controls (p = 0.002). There were no significant differences in IL‐35 levels between benign and malignant SGTs (p = 0.133). In OSCC patients, IL‐35 levels did not significantly differ from those in the control group (p > 0.05). Furthermore, OSCC tumor characteristics, including tumor origin and lymphatic involvement, showed no significant correlation with IL‐35 levels (p > 0.05).

The study indicates that IL‐35 levels are notably reduced in SGTs compared to healthy individuals. However, no significant difference was observed between benign and malignant SGTs. The absence of significant correlation in OSCC patients suggests that IL‐35 may have a minor role in this type of cancer, highlighting the potential need for other biomarkers to improve early detection.