Abstract
OBJECTIVE: Lung adenocarcinoma (LUAD) is one of the most common and lethal tumors. The identification of diagnostic and prognostic biomarkers is essential to improve patient prognosis and treatment outcomes. METHODS: The expression of minichromosome maintenance complex component 8 (MCM8) in 33 cancer types was analyzed using the Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression. Tumor and normal tissues in LUAD were compared using TCGA data and validated against four datasets from the Gene Expression Omnibus. MCM8 expression was assessed by immunohistochemistry (IHC) using tissue microarrays. The diagnostic value of MCM8 was assessed by Receiver Operating Characteristic curve analysis, and its prognostic significance was determined by Kaplan-Meier analysis. The CIBERSORT method was used to examine immune infiltration. The association between MCM8 expression and m6A RNA methylation, glycolysis, and ferroptosis was assessed using the GEPIA online tool. RESULTS: MCM8 is markedly overexpressed in many tumors including LUAD. MCM8 showed high accuracy for the diagnosis of LUAD, with an area under the curve of 0.849 in TCGA dataset. MCM8 overexpression in tumor tissues in LUAD was confirmed by IHC and shown to be associated with decreased overall survival and disease-specific survival. Analysis of immune cell infiltration showed that immune cell populations differed between high and low MCM8 expression groups. MCM8 expression correlated with that of genes associated with m6A RNA methylation, glycolysis, and ferroptosis. CONCLUSIONS: MCM8 was identified as a promising diagnostic and prognostic marker in LUAD. The mechanism underlying the effect of MCM8 on cancer development and the immune response remains to be elucidated.