PD-L1 expression in meningiomas.

Area of Science:

• Neuro-oncology
• Immunology
• Pathology

Background:

• Meningiomas, particularly aggressive or recurrent types, pose management challenges due to limited chemotherapy options.
• Tumor-induced immunosuppression is a known factor in cancer progression.
• Programmed death-ligand 1 (PD-L1) is implicated in immune evasion in various cancers.

Purpose of the Study:

• To determine the prevalence and extent of PD-L1 expression in a series of meningiomas.
• To assess the potential of PD-L1 as a therapeutic target in meningioma treatment.

Main Methods:

• Utilized an FDA-approved monoclonal antibody for PD-L1 immunohistochemical screening.
• Analyzed 58 meningioma samples, including 13 with invasion (bone, brain, or dura).
• Assessed PD-L1 immunoreactivity across different WHO grades and invasion sites.

Main Results:

• PD-L1 expression was detected in a small fraction of meningiomas: 1/31 grade I, 1/16 grade II, and 2/11 WHO grade III.
• Limited PD-L1 immunoreactivity was observed in specific invasive tumors, but not at the invasion sites.
• Overall, PD-L1 expression was found to be limited in the studied meningioma cohort.

Conclusions:

• PD-L1 expression in meningiomas is infrequent and generally limited.
• Anti-PD-L1 therapy may hold potential for a select group of meningioma patients with positive PD-L1 expression.
• The broad applicability of anti-PD-L1 therapy for meningiomas appears limited based on current findings.