Biliary microbiota and metabolic reprogramming in gallstone-associated gallbladder cancer: evidence from bile, stones, mucosa and tumor tissue

Gallbladder cancer (GBC) commonly arises in gallbladders affected by cholelithiasis and chronic cholecystitis, although malignancy develops in only a small minority of patients with stones. This disparity has directed attention to the local conditions created by concentrated bile, stone surfaces, persistent microbes and altered bile acid and lipid metabolism. Evidence in this field is difficult to compare because bile, stones, mucosa and tumor tissue measure different biological processes, while human associations, animal experiments and cross-sectional omics studies are often discussed together. We evaluated microbiological, metabolic and tissue-level studies according to the material examined, disease endpoint and study design, covering gallstone formation, chronic epithelial injury, preneoplastic lesions and established GBC. Salmonella is the most extensively studied microbial candidate, but epidemiological estimates vary with carrier prevalence, detection method and the use of gallstone controls. Fungal findings in GBC currently derive from one exploratory peptide-classification study, whereas separate fungal experiments concern gallstone formation. TMAO has reproducible effects on biliary cholesterol handling and lithogenesis; its relation to GBC is based on cross-sectional plasma measurements and preneoplastic histology in lithogenic-diet mice, without invasive cancer in that model. Single-cell and spatial studies identify epithelial stress, myeloid recruitment, T-cell exhaustion and stromal remodeling in sampled tissues, but precursor lesions remain sparse and pseudotime does not represent clinical follow-up. Bile lipidomics, microbial peptides and circulating markers may aid preoperative assessment when tested against inflammatory gallbladder disease. Distinguishing the material examined and the measured endpoint separates evidence for stone formation, persistent mucosal injury and established cancer, and identifies where paired bile, stone, mucosal and tumor samples can answer specific biological questions.