PD-L1 expression in tongue squamous cell carcinoma

Area of Science:

• Oncology
• Immunology
• Head and Neck Cancer Research

Background:

• Programmed cell death 1 (PD-1) and its ligand PD-L1 are key immune checkpoint proteins.
• These proteins are critical therapeutic targets in head and neck cancers, including tongue SCCs.
• Understanding PD-L1 expression is vital for predicting prognosis and guiding treatment strategies.

Purpose of the Study:

• To investigate the correlation between PD-L1 expression and clinical prognosis in tongue squamous cell carcinomas (SCCs).
• To analyze PD-L1 expression in a large cohort of tongue SCC cases.
• To establish this as the largest case study on PD-L1 expression in tongue SCCs to date.

Main Methods:

• A retrospective case-control study involving 121 tongue SCC cases.
• Immunohistochemistry was utilized to assess PD-L1 expression on paraffin-embedded tissue sections.
• Clinical data, including prognosis and nodal metastasis, were analyzed in conjunction with PD-L1 status.

Main Results:

• 11.6% of cases exhibited high PD-L1 expression (≥50% positive cells), with 57.1% of these showing poor prognosis and nodal metastasis.
• High PD-L1 expression was significantly associated with shorter disease-free survival in T1/2 primary lesions with nodal metastasis (p=0.018).
• The adjusted hazard ratio for high PD-L1 expression was 3.21, indicating a substantially increased risk compared to no PD-L1 expression.

Conclusions:

• Upregulation of PD-L1 in tongue SCCs is linked to more advanced disease stages and reduced disease-free survival.
• PD-1/PD-L1 inhibitors show promise as potential adjuvant therapies for tongue SCC patients with elevated PD-L1 expression.
• These findings highlight PD-L1 as a significant prognostic biomarker in tongue SCC.