Impact of Electronic Nicotine Delivery Systems on Oral Mucosa: A Cytopathological and Molecular Study

Background The packaging and marketing of electronic cigarettes (e‐cigs) often target younger demographics. This study aimed to evaluate gene expression in e‐cig users through exfoliative cytology. Methods Samples were collected from 17 e‐cig users and 10 nonsmokers as controls. Clinical data included age, gender, heart rate, oximetry, capillary blood glucose, carbon monoxide levels, sialometry, alcohol‐related risk scores, alcohol consumption, and e‐cig use parameters. Smears from the left tongue edge were obtained using a Rovers Orcellex Brush. The Papanicolaou method assessed epithelial maturation and cytological features, categorized from normal to conclusive for malignancy. Cellular composition, inflammation, microbial presence, and atypia were evaluated using a semiquantitative scoring system. Gene expression (p16, IL1‐beta, CXCL8, TNF, and KRT13) was analyzed by RT‐PCR. Statistical comparisons used the Mann–Whitney test, and correlations were assessed via Spearman's test ( p ≤ 0.05). Results Fruit flavors were the most preferred. Some users were former smokers (average abstention: 3.15 months). Bacterial colonies were more prevalent in the e‐cig group (64.7% vs. 20%, p = 0.085), mucus and inflammatory changes were found exclusively in e‐cig users ( p = 0.062). No significant differences were found in the Papanicolaou classification by gender ( p = 0.904). Gene expression analysis showed a differential expression of p16 and TNF between the groups. Significant correlations were found between carbon monoxide and p16 expression ( r = −0.41, p = 0.02), vaping sessions per day and p16 expression ( r = −0.37, p = 0.02), and daily alcohol dose and TNF expression ( r = −0.42, p = 0.04). Conclusion E‐cigarette use may induce early molecular and cytological changes in the oral mucosa, affecting inflammation, immunity, and epithelial differentiation.