SMC2 as a potential prognostic biomarker in lung adenocarcinoma and its correlation with immune microenvironment

Structural maintenance of chromosome 2 (SMC2) has been recognized to play an important role in a variety of cancers, but its function in lung adenocarcinoma (LUAD) remains poorly understood. Our research utilized various databases and analytical tools such as The Cancer Genome Atlas, TIMER 2.0, TISIDB, cBioportal, Gene Ontology, Gene Set Enrichment Analysis (GSEA) and Kyoto Encyclopedia of Genes and Genomes, for analyzing SMC2 expression, prognosis significance, immune features and gene alterations in LUAD. In addition, quantitative polymerase chain reaction and immunohistochemistry were used to detect SMC2 expression in LUAD. The clinical data of 70 patients with LUAD in Hunan Provincial People's Hospital were analyzed. SMC2 was markedly upregulated in LUAD cell lines and tissues and was strongly correlated with adverse clinicopathological features and prognosis. The enrichment analysis suggested that SMC2 might be involved in the regulation of LUAD cell cycle. The TIMER algorithm and single-sample GSEA algorithm showed that SMC2 was associated with suppressive immune cells (for example, B cells) in LUAD. In addition, SMC2 may interact with the expression of poor prognostic molecules to promote LUAD progression. Evidence from the TISIDB database revealed that SMC2 is positively associated with immunosuppressive genes. However, it is inversely associated with chemokines and receptors. Also, as predicted by the tumor immune dysfunction and exclusion algorithm, patients with high SMC2 expression responded poorly to immunotherapy. These findings suggest that SMC2 is associated with the malignant progression of LUAD and therefore may be a potential target for improving outcomes in LUAD in the foreseeable future.