Comparison of PD-L1 Expression Status between Pure-Solid Versus Part-Solid Lung Adenocarcinomas.

Area of Science:

• Oncology
• Immunology
• Pulmonary Medicine

Background:

• Lung adenocarcinomas (LADs) present as part-solid tumors with ground-glass opacity (GGO) or pure-solid tumors.
• Clinicopathological features and prognoses differ between these LAD subtypes.
• The expression of programmed death ligand-1 (PD-L1), a key immunotherapy target, in relation to GGO presence is not well understood.

Purpose of the Study:

• To investigate whether programmed death ligand-1 (PD-L1) protein expression differs between lung adenocarcinomas (LADs) with and without ground-glass opacity (GGO).
• To compare PD-L1 positivity and high PD-L1 tumor proportion score (TPS) in part-solid versus pure-solid LADs.

Main Methods:

• Retrospective analysis of 124 patients with clinical T1a-c LAD who underwent pulmonary resection.
• Immunohistochemical staining for PD-L1 on primary tumor specimens using the E1L3N antibody.
• PD-L1 positivity defined as ≥1% tumor cell membrane staining; high PD-L1 TPS defined as ≥50%.

Main Results:

• Pure-solid LADs (n=79) showed significantly higher rates of PD-L1 positivity (25%) and high PD-L1 TPS (16%) compared to part-solid LADs (n=45) (4% and 2%, respectively; p<0.01 and p=0.02).
• Multivariate logistic regression indicated significantly higher odds ratios for PD-L1 positivity (5.9) and high PD-L1 TPS (8.0) in pure-solid LADs.
• No significant differences in clinical factors were observed between the two groups.

Conclusions:

• Lung adenocarcinomas with GGO (part-solid) are associated with a lower incidence of PD-L1 expression compared to pure-solid tumors.
• This difference in PD-L1 expression may have implications for predicting immunotherapy response in distinct LAD subtypes.
• Further research is warranted to explore the clinical significance of these findings.