Differential gene expression profiles of pancreatic ductal adenocarcinomas among African American and Caucasian American patients

PURPOSE: In the United States, African Americans (AA) have higher Pancreatic ductal adenocarcinoma (PDAC) incidence and mortality rates than Caucasian Americans (CA). This study aimed to identify distinct gene expression signatures and differentially regulated pathways in AA and CA PDACs. METHODS: Transcriptomic analyses were conducted on FFPE sections of PDACs (n = 40) from AA (9 PDACs/3 normal) and CA (31 PDACs/5 normal) tissues to evaluate the differential expression and signaling pathways within and between racial groups and to identify distinctive and common genes/pathways. RESULTS: We identified unique differentially expressed genes in both racial groups. Distinct set genes were modulated in AA and CA PDACs, compared to their respective normal tissues. Thirteen genes (seven upregulated and six downregulated) were differentially modulated in AA PDACs vs. CA PDACs. CIBERSORT analysis revealed distinct immune cell composition, with increased resting NK cells and activated mast cells, in AA PDACs, and higher CD4 memory T cells present in CA PDACs. Canonical subtype analyses indicated a more heterogenous subtype distribution in AA PDACs, whereas CA PDACs showed a predominance of classical subtypes. Using a publicly available database, we analyzed the top 25 upregulated genes (normal vs. tumor) for AA and CA racial groups and seven differentially upregulated genes in AA PDACs vs. CA PDACs comparison for associations with survival outcomes. Eight genes (CHST15, PARP15, NUDT16, SERPINB3, PADI1, H3C8, ZNF488, and LETM2) correlated with poor patient survival. CONCLUSION: These findings show distinct gene expression profiles and modulated pathways in AA and CA PDACs, supporting development of race-based therapeutic targets.