Association between programmed cell death ligand 1 expression and thyroid cancer: A meta-analysis

Area of Science:

• Oncology
• Immunology

Background:

• Programmed cell death ligand 1 (PD-L1) is frequently overexpressed in various cancers and linked to patient prognosis.
• Thyroid carcinoma incidence is rising globally, yet PD-L1's role in this cancer remains understudied.

Purpose of the Study:

• To investigate the association between PD-L1 expression and clinicopathological features in thyroid cancer.
• To explore the prognostic significance of PD-L1 expression for disease-free survival (DFS) and overall survival (OS) in thyroid cancer patients.

Main Methods:

• A comprehensive meta-analysis was conducted using data from multiple databases (Medline, PubMed, Cochrane Library, EMBASE, Web of Science, WanFang, CNKI).
• Included 13 studies encompassing 2546 cases of thyroid cancer.
• Data extraction, risk assessment, and synthesis were performed independently by two reviewers using RevMan 5.3 and Stata 15.1.

Main Results:

• High PD-L1 expression was significantly associated with poorer DFS (HR=3.37) and OS (HR=2.52) in thyroid cancer patients.
• Elevated PD-L1 levels correlated with larger tumor size (≥2cm), tumor recurrence, extrathyroidal extension, concurrent thyroiditis, unifocal tumors, and absence of psammoma bodies.
• Subgroup analyses indicated PD-L1 positivity predicts poor DFS in non-medullary thyroid carcinoma and is linked to recurrence, extrathyroidal extension, and specific features in differentiated thyroid carcinoma (DTC), including BRAFV600E mutation.

Conclusions:

• PD-L1 serves as a significant prognostic marker for thyroid cancer, particularly DTC.
• High PD-L1 expression indicates increased malignancy and poorer outcomes.
• PD-L1 inhibitors represent a potential therapeutic strategy for refractory thyroid cancer.