Abstract
Single-cell sequencing (scRNA-seq) has emerged as a pivotal technology for deciphering the complex cellular heterogeneity and tumor microenvironment (TME) of pancreatic ductal adenocarcinoma (PDAC), positioning it as a critical tool for informing novel therapeutic strategies. This review explores how scRNA-seq reveals diverse cellular subpopulations and their functional roles within the PDAC TME, including malignant epithelial cells with transitional phenotypes, heterogeneous cancer-associated fibroblasts (CAFs), functionally distinct immune cells such as tumor-associated neutrophils (TANs) and macrophages (TAMs), and actively participating neural components like Schwann cells. These cellular constituents form specialized functional units that drive tumor progression, immune evasion, neural invasion, and therapy resistance through metabolic reprogramming, immunosuppressive signaling, and cellular plasticity. The review further examines technological advances in single-cell sequencing from 2023 to 2025, focusing on sample preprocessing innovations, multi-omics integration (combining transcriptomics with epigenomics and proteomics), spatial resolution enhancements, and customized computational tools that address PDAC-specific challenges. Clinically, single-cell sequencing enables precise cellular subtyping, identification of novel biomarkers, and development of personalized therapeutic approaches, including combination therapies targeting specific cellular subpopulations and their interactions. Despite these advances, significant challenges remain in standardizing clinical applications such as liquid biopsy for early detection and tumor microenvironment assessment for diagnostic staging, validating biomarkers like CLIC4, GAS2L1, Cytokeratins, Vimentin and N-cadherin in circulating tumor cells, and comprehensively integrating multi-omics data. Future research focusing on both technology refinement and biological validation will be essential for translating single-cell insights into improved diagnostic and therapeutic outcomes for pancreatic cancer.