Salivary telomere length in oral leukoplakia and oral squamous cell carcinoma: A preliminary case- control study

To evaluate salivary telomere length as a potential non-invasive exploratory biomarker for early molecular alterations associated with oral leukoplakia and oral squamous cell carcinoma.

Forty-five participants were initially recruited: 15 healthy controls, 15 leukoplakia cases, and 15 oral squamous cell carcinoma (OSCC) cases. Two milliliters of unstimulated saliva was collected, and genomic DNA was isolated using the QIAamp DNA Mini Kit (Qiagen, Hilden, Germany). Relative telomere length (RTL) was assessed using quantitative real-time PCR via the comparative $2^{-\Delta \Delta C_t}$ method. Given the non-normal distribution of RTL values (Shapiro-Wilk p < 0.001 in all groups), group variations were evaluated using the non-parametric Kruskal-Wallis test, with Bonferroni-corrected Mann-Whitney U tests for pairwise comparisons.

The mean relative telomere length (RTL) ratios $2^{-\Delta \Delta C_t}$ were 0.41 $\pm$ 1.00 for healthy controls, 0.48 $\pm$ 0.80 for leukoplakia, and 0.61 $\pm$ 0.87 for OSCC. The Kruskal-Wallis test confirmed no significant difference in RTL ranks across the cohorts (H(2) = 2.68, p = 0.261), and Bonferroni-corrected post hoc Mann-Whitney U comparisons showed no significant pairwise differences between any two groups (all p > 0.35), revealing a highly variable, non-significant upward trend in salivary relative telomere length from health to malignancy.

Salivary telomere length exhibits substantial inter-individual variability and a non-significant increasing trend from healthy controls to oral leukoplakia and OSCC. These preliminary findings suggest that relative telomere length may not be a reliable standalone biomarker in its current form and warrants further validation in larger, longitudinal studies.