The spatiotemporal ecosystem of gallbladder cancer: From inflamed areas to invasive margins - Integrating biomechanical injury, the bile microenvironment, precursor lineages, and spatial niches.

Gallbladder cancer (GBC) is usually described as the end point of chronic cholelithiasis-associated inflammation, and yet this linear formulation does not explain why only a small fraction of people with gallstones develop cancer, why histologically similar precursor lesions follow different evolutionary routes, or why invasion preferentially advances through anatomically and immunologically distinct interfaces. We propose a spatiotemporal ecosystem model that links five domains: gallstones and reflux as precipitating conditions; bile as a chemically active habitat; resident or transient microorganisms as context-dependent modifiers; metaplastic, biliary intraepithelial and intracholecystic precursor lineages as alternative epithelial trajectories; and stromal-immune niches that select for invasive phenotypes. Evidence from epidemiology, pathology, genomics, organoid and animal models, single-cell sequencing, and spatial profiling is integrated while preserving distinctions between association, mechanism, and clinical prediction. The strongest causal chain currently links prolonged mechanical or reflux injury with cycles of epithelial loss and repair, metaplastic or dysplastic changes, and acquisition of driver alterations. Microbial findings are biologically plausible and increasingly supported by functional Salmonella studies, but most human biliary microbiome datasets remain small and vulnerable to low-biomass contamination and treatment-related confounding. Precursor studies substantiate the existence of both BilIN progression in affected areas and alternative polypoid or BilIN-independent routes, arguing against a single obligatory sequence. Recent single-cell and spatial studies have identified organized, region-specific interactions among malignant epithelial states, macrophages, exhausted CD8 T cells, neutrophils, endothelial cells, fibroblasts, hepatocytes, and nerves at invasive margins. Liver-facing, serosal, perineural, lymphovascular, and nodal interfaces should not be assumed to share one ecology. These data shift the central question from which mutation is present to where a clone resides, which neighboring cells sustain it, and when the niche becomes permissive. The model suggests testable priorities: longitudinal sampling of high-risk gallbladders, paired bile-mucosa profiling with rigorous controls, lineage-resolved multi-section spatial analysis, and boundary-aware biomarkers validated in prospective cohorts.