Spatial Proteomic Profiling of the Perineural Invasion Niche in Pancreatic Ductal Adenocarcinoma

This OSF project archives and registers the protocol for a single-center retrospective observational cohort study of the perineural invasion niche in pancreatic ductal adenocarcinoma using archived formalin-fixed, paraffin-embedded tissue specimens. The study compares PNI-positive and PNI-negative cases using PhenoCycler-Fusion spatial single-cell proteomic profiling and filter-aided expansion proteomics (FAXP) of PNI-adjacent and matched control tissue regions, together with standardized pathological assessment, clinicopathological analyses, and survival analyses. This record is a retrospective protocol registration and research timestamp rather than a prospective clinical trial registration. No patient-level data, identifiable clinical information, or identifiable pathological images will be uploaded.