Potential role of inflammation promoting biliary microbiome in primary sclerosing cholangitis and cholangiocarcinoma

This is the first study to investigate both bile and stool microbiota profiles in PSC and CCA, mostly perihilar CCA. Samples with less than 2,000 reads were excluded from the compositional analysis to reduce false associations. We adjusted for demographic and clinical factors influenc-ing the biliary and stool microbiota in PSC and CCA patients. Bile and stool have very different profiles of microbiota, although the bile and stool microbiome from the same subject showed more similarity than those from different subjects. Increased species richness and abundance of Fusobacteria in bile was correlated with the duration of PSC and also characterized the bile of CCA patients. The unique microbial signature in the bile of patients with CCA raises the possibil-ity of a role for microbiota-driven inflammation in the pathogenesis of perihilar CCA