Prognostic Effectiveness of PD-L1 Tumoral Expression in Oral Cavity Squamous Cell Carcinoma.

Abstract

PD-L1 is a glycoprotein present on antigen-presenting cells and malignant cells and activates the PD-L1 receptor on cells surfaces, leading to T-cell anergy and death. The objective of this study was to assess PD-L1 tumoral expression in 50 patients with oral squamous cell carcinoma, define its prognostic value, and investigate its association with 2-year overall survival, locoregional recurrence, distant metastasis, and a number of other clinicopathological parameters. In a 24-month prospective observational study, involving 50 oral cavity squamous cell carcinoma patients, PD-L1 tumoral expression was evaluated using semiquantitative immunohistochemistry analysis by an experienced pathologist. PD-L1 expression of ≥ 6% of tumor cells was associated with poor survival outcome and determined to be a pertinent clinical cutoff value. PD-L1 expression of ≥ 6% was significantly associated with a number of clinicopathological parameters in our study of 50 patients with OSCC. Pathological nodal staging (P = 0.00), lympho-vascular invasion (P = 0.03), extra-nodal extension (P = 0.04), overall staging (P = 0.01), locoregional recurrence (P = 0.00), and distant metastasis (P = 0.00) all showed statistically significant associations. Our study concluded a significant correlation with decreased 2-year overall survival and 2-year disease free survival by using the Kaplan- Meier survival plot for overall survival (p = 0.02) and (p = 0.0002), respectively. The presence of ≥ 6% PD-L1 (CD274) tumoral expression was found to be significantly associated with 2-year overall survival (OS), locoregional recurrence (LRC), distant metastasis (DM), and various clinicopathological parameters. Tumoral PD-L1 was found as a discrete prognostic biomarker which showed significant association with tumor aggressiveness.