Schwann Cell-Mediated M2-Like Macrophage Polarization in Rhabdomyosarcoma.

Objective: To investigate the cellular components and immunological characteristics of the head and neck rhabdomyosarcoma (RMS) microenvironment.

Methods: We conducted single-cell transcriptomics to analyze the cellular components of the RMS microenvironment. CellChat was utilized for analyzing intercellular interactions. The cancer genome atlas database was used for validation. CIBERSORT was applied for immune infiltration profiling. Functional enrichment analyses were performed using the Kyoto Encyclopedia of Genes and Genomes. Gene set scores were calculated using single-sample gene set enrichment analysis. Subcutaneous allograft models and bulk RNA sequencing were used for validation. Flow cytometry and immunohistochemistry were used to identify M2-like macrophages.

Results: Our findings revealed an extremely low presence of neutrophils in RMS samples compared with normal sample. RMS sample with high Schwann cell infiltration exhibited an increase in M2-like macrophage infiltration. Receptor-ligand pairs, specifically MIF-CD74 and PTN-SDC3, were identified between Schwann cells and M2-like macrophages. In the RMS sample characterized by significant Schwann cell infiltration, M2-like macrophages demonstrate robust expression of axon guidance factors and are enriched in the axon guidance pathway.

Conclusions: Our study provides valuable insights into the microenvironment and immunological characteristics of RMS, offering crucial information for further research and potential therapeutic strategies.