Immune-related markers define clinically relevant prognostic subgroups in thymic epithelial tumors

Area of Science:

• Oncology
• Immunology
• Pathology

Background:

• Characterizing the immune landscape of thymic epithelial tumors (TETs) is crucial for developing immunotherapies and optimizing patient follow-up.
• This study investigates the expression patterns and clinical significance of five immune-related markers in a large cohort of TETs.

Purpose of the Study:

• To examine the expression of TIM3, OX40L, GTF2I, XPO1, and GITR in TETs.
• To correlate immune marker expression with clinicopathological parameters and patient outcomes.
• To identify distinct TET subgroups based on immune profiles and assess their prognostic relevance.

Main Methods:

• Immunohistochemistry (IHC) was used to assess the expression of five immune markers (TIM3, OX40L, GTF2I, XPO1, GITR) in epithelial and lymphocytic compartments of 137 TETs.
• Expression levels were correlated with clinicopathological parameters and patient survival outcomes.
• Cluster analysis was employed to group tumors based on their immune marker expression profiles.

Main Results:

• TIM3, GTF2I, and XPO1 showed high epithelial expression in TETs, while GITR was largely absent.
• Epithelial and lymphocytic OX40L expression was significantly higher in patients with myasthenia gravis.
• Hierarchical clustering identified four distinct TET subgroups with significantly different survival outcomes (p < 0.0001), with one subgroup showing worse survival (HR 6.37; p=0.025).

Conclusions:

• TIM3, GTF2I, and XPO1 are highly expressed in the epithelial compartment of TETs, supporting their potential as therapeutic targets for immunotherapy.
• The differential expression of these immune markers defines distinct TET subtypes with independent prognostic value.
• This immune profiling enables more accurate risk stratification for patients with these heterogeneous thoracic malignancies.