Combined single-cell transcriptome and Mendelian randomization to identify and validate prognostic genes associated with endoplasmic reticulum stress and butyrate metabolism in lung adenocarcinoma.

Background: Lung adenocarcinoma (LUAD) is a prevalent and aggressive subtype of lung cancer, with a 5-year survival rate below 20% due to late-stage diagnosis and drug resistance. Endoplasmic reticulum stress (ERS) and butyrate metabolism (BM) play critical roles in tumor progression, but their co-regulatory features in LUAD remain unclear. Methods: This study integrated single-cell transcriptome analysis and Mendelian randomization (MR) to identify prognostic genes associated with ERS and BM in LUAD. Public datasets were analyzed using weighted gene co-expression network analysis, differential expression analysis, and MR. A risk model and nomogram were constructed, and immune microenvironment, gene set enrichment, and single-cell analyses were performed to validate findings. Moreover, the expression of prognostic genes was validated in different Non-small cell lung cancer (NSCLC) cell lines through reverse transcription quantitative polymerase chain reaction (RT-qPCR). Results: Seven prognostic genes ( Conclusion: This study identifies seven ERS- and BM-related prognostic genes and highlights macrophages as pivotal in LUAD progression, the expression differences of candidate genes were verified by RT-qPCR assay. These findings provide novel insights into LUAD diagnosis, prognosis, and potential therapeutic targets, offering a foundation for precision medicine strategies. Further validation in clinical cohorts and functional studies is warranted to translate these discoveries into clinical applications.