PD-L1 and LAG-3 expression in advanced cutaneous squamous cell carcinomas

Area of Science:

• Oncology
• Immunology
• Dermatology

Background:

• Programmed death ligand 1 (PD-L1) expression in cutaneous squamous cell carcinoma (cSCC) correlates with advanced disease and metastasis.
• Lymphocyte-activation gene 3 (LAG-3) interacts with PD-L1, indicating immune exhaustion and potential immunotherapy targets.
• The role of LAG-3 in cSCC has not been previously established.

Purpose of the Study:

• To investigate the expression of PD-L1 and LAG-3 in tumor-infiltrating lymphocytes (TILs) in advanced cSCC.
• To determine the correlation between PD-L1, TILs, and LAG-3 expression in cSCC.
• To explore LAG-3 as a potential therapeutic target in advanced cSCC.

Main Methods:

• Retrospective review of 18 cases of locally advanced and/or metastatic cSCC.
• Assessment of PD-L1 expression.
• Evaluation of TILs and LAG-3 expression on TILs.

Main Results:

• PD-L1 was expressed in 11/13 locally advanced primary tumors and 5/5 metastases.
• TILs were present in all 18 tumors.
• LAG-3 expression was detected in 14/18 cases, with an average of 32% of TILs expressing LAG-3.

Conclusions:

• Advanced cSCC frequently expresses PD-L1 and shows an inflammatory response.
• LAG-3 expression on TILs is common in advanced cSCC.
• LAG-3 positive tumor-associated inflammatory cells may contribute to disease progression and represent a potential drug therapy target.