# Evaluation of Programmed Death-Ligand 1 (PD-L1) Expression and Its Correlation With Clinicopathological Parameters in Oral Squamous Cell Carcinoma: A Tertiary Care Center Study

## TL;DR

This study examines PD-L1 expression in oral cancer samples and finds it correlates with cancer stage, nerve invasion, and male gender.

## Contribution

The study demonstrates that PD-L1 expression in larger resection specimens provides more meaningful correlations with clinical features than biopsy samples.

## Key findings

- PD-L1 tumor proportion score (TPS) was significantly correlated with cancer stage (P = 0.01).
- Combined proportion score (CPS) was associated with perineural invasion (P = 0.04) and higher in males (P < 0.05).
- Larger resection specimens showed higher PD-L1 expression rates compared to biopsy samples.

## Abstract

Introduction

This study endeavors to evaluate the frequency of programmed death-ligand 1 (PD-L1) expression in oral squamous cell carcinoma (OSCC) specimens and to correlate these findings with clinicopathological features of established prognostic significance.

Methodology

The study included paired pre-surgical biopsy and resection specimens from 35 patients with OSCC. Immunohistochemistry was performed for PD-L1 (clone SP263) with 51.4% tumor proportion score (TPS) and 77.1% combined proportion score (CPS), which was assessed at a cut-off of ≥1%. The association of the mean expression of the biomarker with clinicopathological parameters has been evaluated.

Results

TPS of PD-L1 expression at the cut-offs of ≥1%, ≥10%, ≥25%, and ≥50%, and the positivity rates were 20% (7/35), 8.6% (3/35), 8.6% (3/35), and 14.3% (5/35), respectively. The CPS at the same cut-offs were 22.9%, 31.4%, 17.1%, 11.4%, and 17.1%, respectively. TPS was significantly correlated with stage (P = 0.01), while CPS was associated with perineural invasion (P = 0.04) and showed increased expression in the male population (P < 0.05).

Conclusions

This study highlights the significance of a larger/resection specimen over a small biopsy for PD-L1 evaluation. Increased PD-L1 expression observed in higher-stage disease, perineural invasion (PNI), and male patients can be validated in a larger cohort and potentially guide the use of anti-PD-L1 therapy in OSCC.