TCN1 is a potential prognostic biomarker and correlates with immune infiltrates in lung adenocarcinoma

BACKGROUND: Around the world, lung cancer is the leading cause of cancer-related death. Lung adenocarcinomas are among the most common diagnosed forms of lung cancer, whose overall survival has not improved significantly, which makes finding an effective therapeutic target vital. Transcobalamin (TCN1) is a vitamin B12-binding protein which regulates cobalamin homeostasis. In tumor tissues, TCN1 is expressed highly, and its expression is correlated with cancer aggressiveness and poor prognosis according to recent studies and bioinformatic analyses. However, its effect on lung adenocarcinoma (LUAD) is unknown. METHODS: We evaluated whether TCN1 shows diagnostic and prognostic value in LUAD using bioinformatic analysis. In particular, various databases and analysis tools were used to determine TCN1’s relationship with LUAD, including TCGA, GTEx, GEO, STRING, and TISIDB. RESULTS: As compared to normal lung tissue, the level of TCN1 expression in LUAD tissues was significantly higher (P < 0.001). TCN1 also had a good ability to distinguish lung adenocarcinoma from non-lung adenocarcinoma samples [area under the curve (AUC) = 0.788]. According to univariate Cox statistics, high expression levels of TCN1 correlate with poor overall survival (OS) in LUAD (P < 0.001). Moreover, based on a multivariate Cox analysis, TCN1 expression was independently correlated with OS (P = 0.011). GO/KEGG and GSEA indicated enrichment in epidermal cell differentiation (P < 0.0005), keratinocyte differentiation (P < 0.0005), neuroactive ligand–receptor interaction (P < 0.0005), epithelial–mesenchymal transition (P = 0.029, FDR = 0.023) and TNFA signaling via NFKB (P = 0.029, FDR = 0.023). Furthermore, TCN1 is associated with immune infiltration based on an analysis of immune cell infiltration. CONCLUSIONS: In summary, TCN1 could be used as a prognostic and diagnostic biomarker and provide deeper perspectives for the development of therapies and prognostic markers in LUAD.