Gut microbial composition changes in bladder cancer patients: A case-control study in Harbin, China.

Background and Objectives: This study aimed to explore the changes of gut bacteria in bladder cancer patients. Methods and Study Design: Newly diagnosed bladder cancer patients were recruited. All participants completed a questionnaire about personal behavior and diet. Pyrosequencing of the total genomic DNA extracted from human feces was carried out by Illumina HiSeq 2000. The copy number of target DNA for bacteria was determined by real-time quantitative PCR assay. Fecal short chain fatty acids contents were measured by gas chromatography (GC) analysis. The concentrations of lipopolysaccharide and D-lactic acid in serum were determined by enzyme-linked immunosorbent assay kits. Results: Fruit intake was significantly lower than in healthy controls. The numbers of Clostridium cluster XI and Prevotella in bladder cancer patients decreased. The numbers of domain bacteria and Prevotella were significantly and positively associated with fruit intake (r=0.002, p＜0.05 for domain bacteria; r=0.004, p＜0.05 for Prevotella). The concentration of butyric acid decreased significantly in bladder cancer patients, and the quantities of fecal butyric acid were significantly and positively associated with fruit intake (r=0.610, p＜0.01). The concentrations of lipopolysaccharide and D-lactic acid, two sensitive markers of gut permeability, were greater in bladder cancer patients. Conclusions: Dysbiosis of gut microbiota, decreased butyric acid concentrations and impaired intestinal structural integrity were found in bladder cancer patients, which might be associated with inadequate fruit intake.