Immunological insights into gastric polyps: pathogenesis, inflammation and neoplastic potential

Abstract

Gastric polyps are a heterogeneous group of mucosal lesions increasingly detected during routine endoscopy, encompassing entities with distinct pathogenesis, immune landscapes and variable malignant potential. Accumulating evidence highlights the central role of gastric mucosal immunity in driving polyp initiation, progression, and, in select subtypes, neoplastic transformation. This review synthesises current knowledge on the immunopathogenesis of major gastric polyp subtypes, including hyperplastic, fundic gland, adenomatous, neuroendocrine and inflammatory fibroid polyps, with a particular emphasis on the interplay between chronic inflammation, epithelial injury and immune-mediated tissue remodelling. We discuss how Helicobacter pylori infection, autoimmune gastritis, proton pump inhibitor–induced hypergastrinemia and genetic syndromes shape distinct immune microenvironments characterised by specific cytokine profiles, immune cell infiltrates and epithelial responses. Special attention is given to mechanisms linking sustained immune activation to dysplasia and carcinogenesis, including oxidative stress, cytokine-driven proliferation, immune surveillance failure and early engagement of immune checkpoint pathways such as PD-1/PD-L1. Furthermore, we explore emerging diagnostic, prognostic and therapeutic implications of immune profiling in gastric polyps, ranging from H. pylori eradication and chemoprevention to the potential role of immunomodulatory strategies in high-risk lesions. By integrating immunology with histopathology and clinical behaviour, this review provides a comprehensive framework for understanding gastric polyp biology and identifies key gaps and future directions for precision surveillance and immune-targeted prevention of gastric neoplasia.