Comprehensive bioinformatics analysis of EXOSC family genes in lung adenocarcinoma

The RNA exosome complex (EXOSC1-10) orchestrates 3^'-5^' RNA processing and decay, yet its family-wide landscape and clinical relevance in lung adenocarcinoma (LUAD) remain incompletely defined. Here, we conducted an integrative multi-omics analysis of EXOSC family members in LUAD using public transcriptomic and proteomic resources, external validation cohorts, and single-cell data. Across TCGA (59 normal vs. 515 tumors), all EXOSC genes were significantly upregulated in tumors, with concordant increases for most proteins in CPTAC and immunohistochemistry evidence from the Human Protein Atlas. Survival analyses identified EXOSC2, EXOSC3 and EXOSC5 as prognostically informative, with elevated EXOSC2/EXOSC5 also associated with inferior disease-specific survival. Receiver operating characteristic analyses indicated moderate-to-high diagnostic performance for several EXOSC genes, supported by qRT-PCR validation in LUAD cell lines and confirmation in GSE31210. Clinicopathological correlations linked EXOSC1-5 and EXOSC8-10 to advanced stage and metastatic features, whereas EXOSC6 and EXOSC7 showed comparatively limited or context-dependent associations, suggesting functional heterogeneity within the family. Genomic profiling revealed recurrent alterations in 11.83% of patients, with EXOSC4 exhibiting the highest alteration frequency (predominantly amplifications), and network analyses identified core interacting partners centered on RNA surveillance machinery. EXOSC expression was broadly correlated with RNA modification regulators (m¹A/m⁵C/m⁶A) and displayed heterogeneous relationships with immune checkpoint genes and immune infiltration, while higher EXOSC expression consistently associated with lower ESTIMATE-derived microenvironment scores and an immune profile characterized by Th2/T helper enrichment with reduced cytotoxic and antigen-presenting populations. Gene set enrichment analyses implicated cell-cycle regulation, senescence, chromatin-related programs and extracellular matrix pathways, and EXOSC-high tumors were associated with increased tumor mutational burden and homologous recombination deficiency, together with enrichment of DNA damage response pathways. Single-cell analysis (GSE146100) localized highest EXOSC expression to proliferating monocytes/macrophages and suggested TGF-β-linked communication with endothelial and T-cell compartments. Exploratory translational analyses further indicated an association between EXOSC9 and predicted cisplatin sensitivity. Collectively, these findings position the EXOSC family as a clinically and biologically relevant axis in LUAD, linking RNA surveillance dysregulation to immune contexture and genomic instability, and highlight subunit-specific heterogeneity that warrants mechanistic validation.