PD-L1 expression in recurrent head and neck squamous cell carcinoma

Area of Science:

• Oncology
• Immunotherapy
• Head and Neck Cancer Research

Background:

• Head and neck squamous cell carcinoma (HNSCC) is a significant global health concern.
• Programmed Cell Death Ligand (PD-L1) is a key immune checkpoint molecule implicated in tumor immune evasion.
• Understanding PD-L1 dynamics in HNSCC is crucial for optimizing immunotherapy response.

Purpose of the Study:

• To investigate the expression patterns of PD-L1 in tumor cells (TC) and immune cells (IC) at diagnosis and relapse in HNSCC patients.
• To correlate PD-L1 expression levels with patient survival outcomes following radio(chemo)therapy.

Main Methods:

• PD-L1 expression was assessed using immunohistochemistry in 44 HNSCC patients at diagnosis and relapse.
• Expression was quantified in both TC and IC, categorized into scores 0, 1, 2, and 3 based on percentage of positive cells.
• Survival analysis was performed to evaluate the impact of PD-L1 expression on patient outcomes.

Main Results:

• PD-L1 expression levels in TC and IC showed variability between diagnosis and relapse in several patients.
• A trend towards PD-L1 expression positivity in TC at relapse was observed in a subset of patients.
• Patients with PD-L1 expression demonstrated significantly higher 2-year survival rates (90% vs. 62.5%, p=0.032).

Conclusions:

• PD-L1 expression is dynamic and can change during the course of HNSCC.
• Re-evaluation of PD-L1 expression on biopsies at the time of recurrence is clinically relevant.
• Assessing PD-L1 at relapse may aid in tailoring subsequent treatment strategies for HNSCC patients.