Prognostic and immunological significance of metastasis-associated protein 3 in patients with thymic epithelial tumors.

BACKGROUND: Immune checkpoint inhibitors have shown promising anticancer activity and have recently been proposed as a therapy for thymic epithelial tumors (TETs); however, this treatment is only effective for a subgroup of TET patients. Thus, this study aims to identify the potential genes implicated in the regulation of cancer immunity in TETs. METHODS: The TETs RNA-seq and clinical data were obtained from The Cancer Genome Atlas (TCGA) database. The clinical significance of the tumor microenvironment (TME) in TETs was evaluated. Weighted gene coexpression network analysis (WGCNA) was used to identify the immune response-related hub genes. The expression of metastasis-associated protein 3 (MTA3) in TETs was investigated in public datasets and a patient cohort. Kaplan‒Meier curves were generated to analyze the prognostic value of various factors. The Tumor Immune Estimation Resource (TIMER2.0) was used to estimate the relevance of MTA3 to immune cell infiltration. Gene set enrichment analysis (GSEA) and pathway enrichment analysis were applied to explore the MTA3-related pathways. RESULTS: The TME was found to be clinically significant in TETs. Moreover, MTA3 was identified as a key gene associated with the immune score, and lower MTA3 expression was linked to poor TME and reduced cytotoxic activity in TETs. Furthermore, MTA3 was found to be deregulated in TETs, predictive of poor prognosis. MTA3 was also significantly associated with the infiltration levels of various immune cell types and highly correlated with their corresponding markers. Notably, MTA3 was positively associated with various immune response pathways. CONCLUSION: MTA3 is clinically significant in TETs and correlated with immune cell infiltration. Thus, MTA3 might be a biomarker for predicting the prognosis and immune status of TET patients.