Pilot Study on Rna Sequencing of Pancreatic Cancer Tissue and Peripheral Blood Mononuclear Cells in Pancreatic Ductal Carcinoma Patients: Focus On Ahr-Related Genes

Abstract

Introduction Pancreatic ductal adenocarcinoma (PDAC) accounts for approximately 7% of cancer-related deaths [1]. Despite advancements in cancer research, the five-year survival rate remains at 9%, primarily due to late diagnosis and limited treatment options [2,3]. Investigating differential gene expression between tumor tissue and peripheral blood mononuclear cells (PBMCs) may uncover potential biomarkers and therapeutic targets for early diagnosis and personalized treatment [4,5]. A key target in this pilot study was the aryl hydrocarbon receptor (AHR) and its pathways, implicated in immune suppression, oxidative stress, inflammation, angiogenesis, and tumor progression [6–9]. Aim To analyze transcriptional differences between PBMCs and PDAC tissues, focusing on the AHR signaling and related genes to understand their roles in disease progression. Methods PDAC tissue and PBMC samples were collected from six patients on the day of surgery, including one postneoadjuvant treatment. RNA sequencing libraries were prepared using the ILMN Stranded Total RNA Library with Ribo-Zero PLUS and sequenced on the NextSeq550 platform. Data were processed with the Nextflow RNA-seq workflow, using STAR for sequence alignment and RSEM for transcript quantification. Differential gene expression analyses were performed in RStudio, focusing on AHR signaling and related genes. Results PBMC samples exhibited similar immune gene expression profiles, while PDAC tissues demonstrated greater variability due to tumor heterogeneity and mutations. The principal component analysis identified two outliers: one reflecting the impact of neoadjuvant therapy, showing unique expression patterns, and another linked to a poor prognosis characterized by lymph node involvement and vascular invasion. Targeted gene analysis revealed that IL-4 expression was higher in tumor tissues compared to PBMCs, while AHRR, CYP1A1, IL-6, and IL-10 were more highly expressed in PBMCs than in tumor tissues, indicating immune modulation. Further studies should be done to validate these findings in larger cohorts and explore the impact of neoadjuvant treatments on gene expression to predict patient outcomes and therapeutic responses. Conclusions This study reveals significant transcriptional differences between PBMCs and PDAC tissues, reflecting tumor heterogeneity and variation in immune responses. IL-4 expression was higher in tumor tissues, suggesting its role in tumor progression and immune evasion, while AHRR, CYP1A1, IL-6, and IL-10 were more highly expressed in PBMCs.