PD-L1 Expression in Gliomas: A Potential Immunotherapeutic Target in High-grade Tumours

Area of Science:

• Neuro-oncology
• Immunology
• Cancer Biology

Background:

• Gliomas are primary central nervous system tumors, with glioblastoma being the most aggressive.
• Standard treatments offer limited survival benefits for glioma patients.
• Immune checkpoint inhibitors targeting the PD-1/PD-L1 axis show efficacy in other cancers, but their role in gliomas is under investigation.

Purpose of the Study:

• To evaluate Programmed death-ligand 1 (PD-L1) expression in gliomas.
• To correlate PD-L1 expression with glioma tumor grade.
• To assess the potential of PD-L1 as a biomarker for immunotherapy.

Main Methods:

• Analysis of 50 histologically confirmed glioma cases.
• Tumor grading according to WHO 2021 CNS classification.
• Immunohistochemistry (IHC) for IDH, ATRX, TP53, Ki67, and PD-L1.
• Statistical analysis using ordinal regression.

Main Results:

• PD-L1 expression was exclusively detected in grade 4 gliomas (27.27% of cases).
• No PD-L1 expression was observed in grade 1-3 gliomas.
• A statistically significant association between PD-L1 expression and higher tumor grade (p=0.007) was found.

Conclusions:

• PD-L1 expression is restricted to high-grade gliomas, indicating a potential role in immune evasion.
• PD-L1 may serve as a predictive biomarker for identifying glioma patients eligible for anti-PD-1/PD-L1 immunotherapy.