Supplementary Material for: PDIA5 and ARFIP1 as immunogenetic biomarkers and therapeutic targets in pancreatic neuroendocrine neoplasms: a multi-omics study integrating MR, gene expression microarray and single-cell transcriptomics

Introduction: Pancreatic neuroendocrine tumors (PanNENs) are characterized by significant clinical heterogeneity and limited therapeutic options, particularly in metastatic or recurrent cases. Identifying actionable molecular targets and biomarkers is essential for improving patient outcomes.
Methods: We employed a multi-omics approach to identify biomarkers and therapeutic targets for PanNENs. Two-sample Mendelian randomization (TSMR) was conducted using plasma proteome data from Zheng et al. and deCODE. Differential expression and weighted gene co-expression network analyses (WGCNA) were performed on the GSE73338 dataset to prioritize biomarkers. Validation included cis-eQTL data from eQTLGen and summary data-based MR with heterogeneity in dependent instrument (HEIDI) tests. Immune mediation analysis was performed, followed by transcriptomic validation using gene expression microarrays (GSE43795) and single-cell RNA sequencing (GSE256136) data. Immune infiltration was assessed using CIBERSORT, and protein expression was validated using immunohistochemistry (IHC). Pan-cancer analysis was conducted using TCGA and GTEx data, and diagnostic performance was evaluated using ROC curves and nomograms. Results: PDIA5 and ARFIP1 were identified as potential biomarkers and therapeutic targets for PanNENs. Both proteins were upregulated in PanNEN tissues and showed consistent associations with PanNEN risk through TSMR and SMR analyses. Immune mediation analysis suggested their involvement in immune modulation. Pan-cancer analysis revealed their overexpression in multiple cancer types. Diagnostic performance, evaluated using ROC curves, demonstrated the strong potential of PDIA5 and ARFIP1 in PanNEN diagnosis. Conclusion: PDIA5 and ARFIP1 are promising biomarkers and therapeutic targets for PanNEN. Further validation and clinical exploration are required.