NNMT is a immune-related prognostic biomarker that modulates the tumor microenvironment in pan-cancer

Background: Emerging evidence revealed the significant roles of Nicotinamide n-methyltransferase (NNMT) in cancer initiation, development, and progression, but there is no pan-cancer analysis of NNMT. Here, we aimed to analyze the expression and prognostic value of NNMT in pan-cancer and to gain insights into the association between NNMT and immune infiltration. Methods: : We analyzed NNMT expression patterns and the association between NNMT expression levels and prognosis in pan-cancer via the Oncomine, Tumor Immune Estimation Resource (TIMER), Gene Expression Profiling Interactive Analysis (GEPIA), and Kaplan–Meier Plotter databases. After that, TIMER2 and Immune Cell Abundance Identifier (ImmuCellAI) databases were applied to investigate the relation between NNMT expression and immune infiltration across different cancer types. Signaling pathways related to NNMT expression were identified by gene set enrichment analysis (GSEA). Results: : NNMT was significantly upregulated in various common cancers, and it was associated with prognosis. High expression of NNMT was associated with poor overall survival (OS) and relapse-free survival (RFS) in various common cancers, such as Cervical squamous cell carcinoma and endocervical adenocarcinoma (CESC), head and neck squamous cell carcinoma (HNSC), Ovarian serous cystadenocarcinoma (OV) and stomach adenocarcinoma (STAD). NNMT remarkably correlated with the levels of cancer associated fibroblasts (CAFs) and Macrophage cells infiltration. Conclusion: NNMT may serve as a promising prognostic biomarker in pan-cancer andhas positive association with immune infiltrates.