Abstract
BACKGROUND: Testicular germ cell tumor (TGCT) is the most common malignancy in young males from ages 15 to 44 years, but treatment remains challenging. Emerging evidence indicates that the tumor mutational burden (TMB) may be associated with tumor growth and progression. This study examined the association of TMB with the gene expression profiles and the tumor microenvironment (TME) of TGCT. METHODS: Datasets from the Gene Expression Omnibus (GEO), The Cancer Genome Atlas (TCGA), and Genotype-Tissue Expression (GTEx) databases were analyzed. Differential expression analysis was applied to identify TMB-related genes via DESeq2 in TCGA. Further protein-protein interaction (PPI) network analysis, including module and degree analysis combined with Kaplan-Meier analysis, was applied to identify four hub genes (FOXA2, IRX3, MYH7, and TNNT2). Gene set enrichment analysis (GSEA) demonstrated significant enrichment of immune-related pathways associated with both TMB and hub gene expression profiles. The Human Protein Atlas database, receiver operating characteristic (ROC) curve analysis, and univariable Cox analysis were used to confirm the prognostic implications of hub genes in TGCT. RESULTS: The CIBERSORT algorithm, Wilcoxon rank-sum test, and Spearman analysis were applied to determine the association between TMB, the four hub genes (FOXA2, IRX3, MYH7, and TNNT2), and the infiltration levels of 22 immune cell types. GSEA indicated that TMB and TMB-related hub genes (FOXA2, IRX3, MYH7, and TNNT2) were all highly associated with immune-related function. CONCLUSIONS: Our findings could provide a better understanding of the progression of TGCT and identify potential biomarkers or drug targets for TGCT.