Circulating Plasma Exosomal PD-L1 Predicts Prognosis of Head and Neck Squamous Cell Carcinoma After Radiation Therapy

Area of Science:

• Oncology
• Immunotherapy
• Biomarker Discovery

Background:

• Radiation therapy is a standard treatment for head and neck squamous cell carcinoma (HNSCC).
• Predictive biomarkers are crucial for optimizing HNSCC treatment strategies.
• Programmed death-ligand 1 (PD-L1) is an immune checkpoint protein implicated in cancer progression.

Purpose of the Study:

• To investigate the association between circulating plasma programmed death-ligand 1 (PD-L1) levels and treatment outcomes in HNSCC patients receiving radiation therapy.
• To determine if pretreatment PD-L1, both total and exosomal, can serve as a prognostic biomarker for HNSCC patients.

Main Methods:

• Retrospective analysis of plasma samples from 76 HNSCC patients before radiation therapy.
• Quantification of total and exosomal PD-L1 using enzyme-linked immunosorbent assay.
• Statistical analysis including univariate and multivariate models to assess the correlation between PD-L1 levels and overall survival (OS), progression-free survival (PFS), and local control (LC).

Main Results:

• Median total PD-L1 was 115.1 pg/mL; median exosomal PD-L1 was 2.8 pg/mL.
• Elevated pretreatment exosomal PD-L1 was significantly associated with poorer PFS and LC.
• 1-year PFS was 79.2% for high exosomal PD-L1 vs. 33.3% for low (P < .001).
• 1-year LC was 87.3% for high exosomal PD-L1 vs. 50.0% for low (P < .001).
• Total PD-L1 and exosomal PD-L1 did not significantly impact OS.

Conclusions:

• Pretreatment circulating exosomal PD-L1 in plasma is a significant prognostic factor for HNSCC patients undergoing radiation therapy.
• Exosomal PD-L1 levels can help predict progression-free survival and local control.
• This finding supports the potential utility of exosomal PD-L1 as a predictive biomarker in HNSCC management.