Significance of immune checkpoint proteins in EGFR-mutant non-small cell lung cancer

Area of Science:

• Oncology
• Immunology
• Molecular Biology

Background:

• Non-small cell lung cancer (NSCLC) with EGFR mutations represents a distinct molecular subtype.
• Immune checkpoint proteins like PD-L1, PD-1, CTLA-4, and TIM-3 play crucial roles in tumor immune evasion.
• Understanding the expression of these markers in EGFR-mutant NSCLC is vital for optimizing immunotherapy strategies.

Purpose of the Study:

• To investigate the expression patterns of PD-L1, PD-1, CTLA-4, and TIM-3 in EGFR-mutant NSCLC.
• To determine the prognostic significance of these immune markers in relation to treatment outcomes with EGFR tyrosine kinase inhibitors (TKIs).

Main Methods:

• Immunohistochemistry was employed to assess the expression of CTLA-4, PD-L1, PD-1, TIM-3, and CD3 in tumor samples from 90 advanced-stage NSCLC patients with EGFR mutations.
• Patients were treated with first-line EGFR TKIs within three months of diagnosis.

Main Results:

• PD-L1 expression was detected in at least 1% of immune cells (44%) and tumor cells (59%) of the samples.
• Higher CD3 immune shaped cell (ISC) counts and high PD-L1 tumor H-score were associated with shorter progression-free survival (PFS).
• High CTLA-4 ISC counts showed borderline significance for overall survival (OS).

Conclusions:

• Tumor PD-L1 expression is significantly linked to shorter PFS in EGFR-mutant NSCLC.
• Immune cell CTLA-4 may serve as a prognostic marker for OS.
• These findings advocate for the continued development of CTLA-4 and PD1/PD-L1 inhibitors in this specific NSCLC subgroup.