CD3 LEVELS IN TUMOR INFILTRATING LYMPHOCYTES ACROSS ORAL SQUAMOUS CELL CARCINOMA STAGES IN TERTIARY CARE HOSPITALS.

Background: Oral squamous cell carcinoma (OSCC) is the most common malignancy affecting the oral cavity, contributing significantly to cancer-related morbidity and mortality, especially in regions with high tobacco consumption. Tumor-infiltrating lymphocytes (TILs), particularly CD3-positive (CD3+) T-cells, play a critical role in the body’s immune response to cancer. However, the relationship between CD3+ T-cells and OSCC progression remains poorly understood. Objective: This study aimed to assess the levels of CD3+ T-cells in TILs across different stages of OSCC and explore their association with tumor progression. Methods: A retrospective cohort study was conducted on 200 patients diagnosed with OSCC at Dentistry Department, Ayub Medical College Abbottabad, Pakistan from January 1, 2023, to December 31, 2023. CD3 levels were evaluated using immunohistochemistry in TILs, with patients stratified based on tumor stage. Baseline characteristics such as age, gender, and tobacco use were recorded. Statistical analysis was performed using ANOVA and chi-square tests for categorical variables, while multivariate logistic regression was employed to identify significant predictors of CD3 expression. Results: CD3 expression progressively increased with advancing OSCC stages. In Stage I, 25 patients (41.7%) had low CD3 expression, while 5 patients (8.3%) exhibited high expression. In Stage IV, only 10 patients (10.8%) had low CD3 expression, with 32 patients (34.9%) showing high expression. Tobacco use was significantly associated with higher CD3 levels (p=0.01). Multivariate analysis identified tumor stage and tobacco use as significant predictors of elevated CD3 expression (OR 2.3, 95% CI 1.3-4.0, p=0.01). Conclusion: The study demonstrates that CD3+ T-cell levels increase with OSCC progression, particularly in tobacco users. These findings suggest that CD3 expression could serve as a potential biomarker for OSCC prognosis, supporting the integration of immunotherapy in advanced-stage OSCC management.