The Prognostic Significance of Programmed Death-Ligand 1 (PD-L1) in Skin Neoplasms: A Systematic Review and...

Area of Science:

• Oncology
• Immunology
• Dermatology

Background:

• Programmed death-ligand 1 (PD-L1) is an immune checkpoint molecule with established therapeutic and prognostic roles.
• The prognostic significance of PD-L1 in various skin neoplasms is not fully understood and remains controversial.

Purpose of the Study:

• To systematically evaluate the prognostic value of PD-L1 expression in overall survival (OS) and disease-free survival (DFS) across different skin neoplasms.

Main Methods:

• A meta-analysis of 24 studies systematically searched from PubMed, Scopus, and Web of Science databases up to March 2025.
• Outcome measures included OS and DFS, with subgroup analyses conducted based on tumor type.
• Heterogeneity and publication bias were assessed using I² statistics and funnel plots.

Main Results:

• Overall, PD-L1 expression did not significantly correlate with OS (HR=0.89) or DFS (HR=0.86).
• Subgroup analysis revealed improved OS with PD-L1 expression in Merkel cell carcinoma (HR=0.39).
• PD-L1 predicted better DFS in melanoma and cutaneous squamous cell carcinoma, but worse DFS in cutaneous angiosarcoma and sebaceous gland carcinoma. PD-L1 also correlated with lymph node metastasis risk in squamous cell carcinoma (OR=5.33).

Conclusions:

• The prognostic impact of PD-L1 expression in skin neoplasms is highly subtype-specific.
• PD-L1 may indicate improved survival in certain skin cancers like Merkel cell carcinoma, while predicting poorer outcomes in others such as cutaneous angiosarcoma and sebaceous gland carcinoma.