Abstract
Despite extensive research highlighting the pivotal role of NOX4 in the development of various malignancies, no systematic pan-cancer analysis has been conducted to evaluate its comprehensive prognostic value and potential immunological functions. In this study, we explored the prognostic significance of NOX4 and its role in immune modulation across different cancer types. We performed a pan-cancer analysis of NOX4 expression and its prognostic implications using multiple databases, including TCGA, GEPIA, GTEx, UALCAN, TISCH, GDSC, PDB, TIMER, and cBioPortal. This analysis provided a detailed assessment of NOX4 expression profiles, clinical correlations, genetic variants, tumor microenvironment interactions, immune relevance, therapeutic potential, and related gene functions through various multi-omics approaches. To further investigate these findings, we collected clinical samples from selected cancer types and validated NOX4 expression through immunohistochemistry, H&E staining, and RT-PCR. Our results revealed that NOX4 was overexpressed in most tumors, although its expression was significantly reduced in certain renal cancers. Moreover, we observed distinct correlations between NOX4 expression and patient prognosis. Notably, NOX4 expression was significantly associated with tumor infiltration, indicating its potential as a target for immunotherapy. Additionally, NOX4 expression showed significant correlations with immune checkpoint proteins (ICP), tumor mutation burden (TMB), microsatellite instability (MSI), RNA stemness scores (RNAss), DNA stemness scores (DNAss), RNA methylation, and DNA methylation.