Redox–Ferroptosis Crosstalk in Pancreatic Ductal Adenocarcinoma: Exploratory Transcriptomic Associations and Cross-Cohort Sensitivity Analyses

Pancreatic ductal adenocarcinoma (PDAC) exhibits oxidative stress adaptation and ferroptosis-associated transcriptional remodeling. We assessed redox- and ferroptosis-related expression scores using public transcriptomic cohorts and evaluated exploratory cross-cohort associations. The historical TCGA–GTEx tumor–normal comparison is potentially confounded by cohort origin and tissue collection, so its differential-expression findings are treated as descriptive rather than independently validated. In tumor-only analyses, the association between RedoxScore and FerroBalance differed between GSE15471 (Spearman ρ = −0.304, p = 0.0602) and GSE85916 (ρ = 0.243, p = 0.0299). In GSE85916, redox stratification was not associated with overall survival (log-rank p = 0.3313); the continuous Cox association was also non-significant (HR = 1.072, 95% CI 0.580–1.982; p = 0.8251). Four median-defined groups are therefore presented as descriptive quadrants, not validated molecular subtypes. These exploratory findings motivate further assessment using versioned gene sets, within-source comparisons, and molecular subtype annotations.