EXPRESSION OF ANTI-PROGRAMMED DEATH-LIGAND 1 AND ANTI-CLUSTER OF DIFFERENTIATION 8 ANTIBODIES IN ORAL SQUAMOUS CELL CARCINOMA: A CROSS-SECTIONAL STUDY

Abstract

Objective: To determine the immunohistochemical expression of anti-PD-L1 and anti-CD8 antibodies in oral squamous cell carcinoma (OSCC).

Methods: A six-month cross-sectional analysis of 150 histopathologically proven OSCC cases was carried out at Khyber College of Dentistry from November 1st to April 30th, 2026. Formalin-fixed paraffin-embedded (FFPE) tissue sections were stained with anti-PD-L1 (clone 22C3) and anti-CD8 antibodies (clones C8/144B). Biomarker expression was compared to clinicopathological factors using chi-square, independent t-test, one-way ANOVA, Spearman association test, and binary logistic regression.

Results: PD-L1 positive was found in 56.0% of patients, with significant CD8+ lymphocyte infiltration in 54.0%. Significant correlations were seen between PD-L1 expression and advanced TNM stage (p0.001), poor histological differentiation (p=0.001), lymph node metastases (p=0.008), and strong CD8 infiltration (p<0.001). The number of CD8+ cells differed significantly between well-differentiated and early-stage tumors (p<0.001). There was a moderate positive correlation between PD-L1 expression and CD8 infiltration (rₛ=0.421, p<0.001). Logistic analysis identified advanced stage, poor differentiation, lymph node positivity, significant CD8 infiltration, and older age as independent determinants of PD-L1 positivity.

Conclusions: In OSCC, PD-L1 expression was substantially related to aggressive clinicopathological characteristics and increased infiltration of immune cells positive for CD8. A panel of immunological biomarkers that includes both PD-L1 and CD8 could be relevant for patient stratification and treatment selection.