Reframing thymic epithelial tumors through single-cell transcriptomics: a narrative review.

Area of Science:

• Oncology
• Immunology
• Genomics

Background:

• Thymic epithelial tumors (TETs) are rare and diverse neoplasms.
• Existing classifications capture features but not full heterogeneity.
• Single-cell transcriptomics offers a high-resolution approach to dissect TET complexity.

Purpose of the Study:

• To review recent single-cell RNA sequencing (scRNA-seq) studies on human TETs.
• To illuminate epithelial subpopulations and the intra-tumoral immune landscape.
• To identify disease-specific aberrations, including myasthenia gravis (MG)-associated phenotypes.

Main Methods:

• Focused narrative review of three key scRNA-seq studies on primary human TETs.
• Analysis of epithelial subpopulations and immune cell interactions.
• Bioinformatic approaches including ligand-receptor network analysis.

Main Results:

• Identification of a novel TEC subpopulation (nmTECs) in MG-associated thymomas, linked to aberrant antigen presentation.
• Delineation of tumor epithelial programs influencing the immune microenvironment and T-cell populations.
• Convergence on functionally oriented classifications based on epithelial programs and immune composition, correlating with prognosis.

Conclusions:

• Single-cell approaches reveal TET heterogeneity, including abnormal epithelial states and immune dynamics.
• These findings refine classification and understanding of TET pathogenesis.
• Further scRNA-seq data will deepen insights into TET biology and normal thymic epithelial cell function.