A novel immune-related microRNA signature for prognosis of thymoma.

INTRODUCTION: Immune microenvironment and microRNAs serve as common predictors for diagnosis and prognosis of tumors. METHODS: Expression of 122 genes and 126 microRNAs in thymoma was obtained from TCGA database. The proportion of tumor-infiltrating cells was calculated, and IMRS was constructed. TREM2hi score was calculated before functional enrichment analysis on gene sets. RESULTS: IMRS3, TREM2hi score, and CD8+ T lymphocyte abundance were significantly different among WHO classifications. WHO classification, Masaoka staging, and miR-130b-5p, miR-1307-3p, miR-425-5p, CD8, CD68, and CCL18 expression were prognostic factors for relapse-free survival and overall survival. IMRS3 upregulation polarized macrophages into M2, which rejected CD8+ T and other effector lymphocytes to promote thymoma malignant progression. CONCLUSIONS: BRRS may present a novel immune-related microRNA signature for TET prognosis.